Tricky Logical Interview Preparation Guide Download PDF
Logical Interview Questions and Answers guide is to build the basics concepts and The formal systematic study of the principles of valid inference and correct reasoning. Logical Interview Questions and Answers also help all of us in the professional field and getting the preparation of any job or entry test or exams or getting visa etc. Logical Interview Questions and Answers are for everyone who wants to build an extra ordinary knowledge.
54 Logical Questions and Answers:
Table of Contents:
1 :: A tourist is traveling to a village where he meets a man at the junction. there he meets a man and asks him a question what would that be? there are 2 villages 1 is true the other is false..?
ask one people that are you from true village if it will say yes than ask are you saying truth if vilagger say yes then it is frome the fake village othervise it is from truth village
3 :: A banana plantation is located next to a desert. The plantation owner has 3000 bananas that he wants to transport to the market by camel, across a 1000 kilometre stretch of desert. The owner has only one camel, which carries a maximum of 1000 bananas at any moment in time, and eats one banana every kilometre it travels. What is the largest number of bananas that can be delivered at the market?
500 bananas. First camel takes 3000 bananas to point A at 250 km apart from plantation in 3 trips and we will be having 1750 bananas at point A.from there to point B 250 km apart from point A and we will have 1000 bananas at point B. Still we havw to go 500 km and having 1000 bananas in hand so we can deliver 500 bananas in market.
4 :: Below are a number of statements:
1. Precisely one of these statements is untrue.
2. Precisely two of these statements are untrue. 3. Precisely three of these statements are untrue. 4. Precisely four of these statements are untrue. 5. Precisely five of these statements are untrue. 6. Precisely six of these statements are untrue. 7. Precisely seven of these statements are untrue. 8. Precisely eight of these statements are untrue. 9. Precisely nine of these statements are untrue. 10. Precisely ten of these statements are untrue. Which of these statements is true?
The ten statements all contradict each other. So there can be at most one statement true. Now suppose there is no statement true. That would mean that statement 10 indeed would be true, which results in a contradiction. This means that exactly nine statements must be untrue, and thus only statement 9 is true..
5 :: Below is an equation that is not correct yet. By adding a number of plus signs and minus signs between the ciphers on the left side (without changes the order of the ciphers), the equation can be made correct. 123456789 = 100 How many different ways are there to make the equation correct?
There are 11 different ways:
123+45-67+8-9=100
123+4-5+67-89=100
123-45-67+89=100
123-4-5-6-7+8-9=100
12+3+4+5-6-7+89=100
12+3-4+5+67+8+9=100
12-3-4+5-6+7+89=100
1+23-4+56+7+8+9=100
1+23-4+5+6+78-9=100
1+2+34-5+67-8+9=100
1+2+3-4+5+6+78+9=100
Remark: if it is not only allowed to put plus signs and minus signs between the ciphers, but also in front of the first 1, then there is a twelfth possibility:
-1+2-3+4+5+6+78+9=100..
123+45-67+8-9=100
123+4-5+67-89=100
123-45-67+89=100
123-4-5-6-7+8-9=100
12+3+4+5-6-7+89=100
12+3-4+5+67+8+9=100
12-3-4+5-6+7+89=100
1+23-4+56+7+8+9=100
1+23-4+5+6+78-9=100
1+2+34-5+67-8+9=100
1+2+3-4+5+6+78+9=100
Remark: if it is not only allowed to put plus signs and minus signs between the ciphers, but also in front of the first 1, then there is a twelfth possibility:
-1+2-3+4+5+6+78+9=100..
6 :: William lives in a street with house-numbers 8 up to and including 100. Lisa wants to know at which number William lives. She asks him: "Is your number larger than 50?" William answers, but lies. Upon this Lisa asks: "Is your number a multiple of 4?" William answers, but lies again. Then Lisa asks: "Is your number a square?" William answers truthfully. Upon this Lisa says: "I know your number if you tell me whether the first digit is a 3." William answers, but now we don't know whether he lies or speaks the truth. Thereupon Lisa says at which number she thinks William lives, but (of course) she is wrong. What is Williams real house-number?
Note that Lisa does not know that William sometimes lies. Lisa reasons as if William speaks the truth. Because Lisa says after her third question, that she knows his number if he tells her whether the first digit is a 3, we can conclude that after her first three questions, Lisa still needs to choose between two numbers, one of which starts with a 3. A number that starts with a 3, must in this case be smaller than 50, so William's (lied) answer to Lisa's first question was "No". Now there are four possibilities: nummer is a multiple of 4 : (16, 36 number is a square) : 8, 12, 20, and more nummer is not a square nummer is not a multiple of 4 : (9, 25, 49 number is a square) : 10, 11, 13, and more nummer is not a square Only the combination "number is a multiple of 4" and "number is a square" results in two numbers, of which one starts with a 3. William's (lied) answer to Lisa's second question therefore was "Yes", and William's (true) answer to Lisa's third question was also "Yes". In reality, William's number is larger than 50, not a multiple of 4, and a square. Of the squares larger than 50 and at most 100 (these are 64, 81, and 100), this only holds for 81. Conclusion: William's real house-number is 81.
7 :: Of all the numbers whose literal representations in capital letters consists only of straight line segments (for example, FIVE), only one number has a value equal to the number of segments used to write it. Which number has this property?
A number having this property is 20 (TWENTY)
T has 3 line segments.
W has 4 line segments.
E has 4 line segments.
N has 3 line segments.
T has 3 line segments.
Y has 3 line segments.
So the total number of line segments are 3+4+4+3+3+3= 20 = TWENTY( the number itself)
T has 3 line segments.
W has 4 line segments.
E has 4 line segments.
N has 3 line segments.
T has 3 line segments.
Y has 3 line segments.
So the total number of line segments are 3+4+4+3+3+3= 20 = TWENTY( the number itself)
8 :: The numbers 1, 2, 3, 4, 5, 6, 7, 8, and 9 must be put in the depicted triangle, in such a way that the sums of the numbers on each side are equal. How should the numbers be arranged in the triangle?
Sum of all the numbers from 1 to 9 is 45 if we divide 45 by 3 we get 15. So the triangle consists of 3 sides so all the three sides should have a sum of 15. So we have
Side 1 : 9+1+5
Side 2 : 3+4+8
Side 3 : 7+6+2.
Side 1 : 9+1+5
Side 2 : 3+4+8
Side 3 : 7+6+2.
9 :: The legendary king Midas possessed a huge amount of gold. He hid this treasure carefully: in a building consisting of a number of rooms. In each room there were a number of boxes; this number was equal to the number of rooms in the building. Each box contained a number of golden coins that equaled the number of boxes per room. When the king died, one box was given to the royal barber. The remainder of the coins had to be divided fairly between his six sons. Is a fair division possible in all situations?
1. At 6 o a clock ticks 6 times. The time between first and last ticks is 30 seconds. How long does it tick at 12?o clock
Answer: 60 Seconds
2. A hotel has 10 story. Which floor is above the floor below the floor, below the floor above the floor, below the floor above the fifth.
Answer: 5th floor.
3. Two trains starting at same time, one from Bangalore to Mysore and other in opposite direction arrive at their destination 1 hr and 4 hours respectively after passing each other. How much faster is one train from other?
Answer: 4 times faster than the other train.
4. A man collects cigarette stubs and makes one full cigarette with every 8 stubs. If he gets 64 stubs how many full cigarettes can he smoke?
Answer: 9 cigarettes.
5. There is one room with 3-bulbs inside and corresponding switches are outside the room. You make any combination of three switches and enter room only once. How do you find out the respective switches for these three bulbs.
Answer: I will switch on the first switch and wait for 5 minutes and then i will turn it off. Then switch on the second switch and then go to the room.
If the bulb is on then its the second switch.
If the bulb is off and cool then its the third switch.
If the bulb is off and hot (as had switched on the first switch for 5 min) then its the first switch
Answer: 60 Seconds
2. A hotel has 10 story. Which floor is above the floor below the floor, below the floor above the floor, below the floor above the fifth.
Answer: 5th floor.
3. Two trains starting at same time, one from Bangalore to Mysore and other in opposite direction arrive at their destination 1 hr and 4 hours respectively after passing each other. How much faster is one train from other?
Answer: 4 times faster than the other train.
4. A man collects cigarette stubs and makes one full cigarette with every 8 stubs. If he gets 64 stubs how many full cigarettes can he smoke?
Answer: 9 cigarettes.
5. There is one room with 3-bulbs inside and corresponding switches are outside the room. You make any combination of three switches and enter room only once. How do you find out the respective switches for these three bulbs.
Answer: I will switch on the first switch and wait for 5 minutes and then i will turn it off. Then switch on the second switch and then go to the room.
If the bulb is on then its the second switch.
If the bulb is off and cool then its the third switch.
If the bulb is off and hot (as had switched on the first switch for 5 min) then its the first switch
10 :: The poor have it, the rich want it, but if you eat it you will die. What is this?
The poor have nothing, the rich wants to do nothing, but if u eat nothing, you will die.
11 :: In a Bus there are 7 people.Each one carry 7 bags. Each bag contains 7 cat.Each cat carry 7 small cats. How many legs are there in the bus?
7*2(people) + 7*7*7*4(cats) + 7*7*7*7*4(small cats) = 10990
12 :: Using the ciphers 1 up to 9, three numbers (of three ciphers each) can be formed, such that the second number is twice the first number, and the third number is three times the first number. Which are these three numbers?
It can be any numbers
2 4 6
1 2 3
3 9 27
and so on.
2 4 6
1 2 3
3 9 27
and so on.
13 :: From a book, a number of pages are missing. The sum of the page numbers of these pages is 9808. Which pages are missing?
We cannot say so because there can be any number of pages missing and whose sum adds up to 9808
14 :: There were 2 doors. one lead to heaven and other to hell there were two doorkeepers one outside each door. one told lie and other spoke truth. what will be one question that czn be asked to both of them so that one comes to know that which door leads to heaven?
We should ask one of them
"What should other man tell if i ask which is the door to heaven?"
Go through the door which he hasn't said
Explanation:
Let two door be A and B
Assume A is the door to heven
Case 1:
Question asked to the lier
The other man always tell the truth so he pick A.But the lier will say B
Case 2:
Question asked to the man who tells truth
The lier will pick B.And the true man tell the truth.
So both will pick B.So go through A the other door
"Question not upto the standard put some complicated one"
"What should other man tell if i ask which is the door to heaven?"
Go through the door which he hasn't said
Explanation:
Let two door be A and B
Assume A is the door to heven
Case 1:
Question asked to the lier
The other man always tell the truth so he pick A.But the lier will say B
Case 2:
Question asked to the man who tells truth
The lier will pick B.And the true man tell the truth.
So both will pick B.So go through A the other door
"Question not upto the standard put some complicated one"
15 :: A man has a wolf, a goat, and a cabbage. He must cross a river with the two animals and the cabbage. There is a small rowing-boat, in which he can take only one thing with him at a time. If, however, the wolf and the goat are left alone, the wolf will eat the goat. If the goat and the cabbage are left alone, the goat will eat the cabbage. How can the man get across the river with the two animals and the cabbage?
There are two solutions: First, the man takes the goat across, leaving the wolf with the cabbage. Then he goes back. Next, he takes the wolf across. Then the man goes back, taking the goat with him. After this, he takes the cabbage across. Then he goes back again, leaving the wolf with the cabbage. Finally, he takes the goat across. First, the man takes the goat across, leaving the wolf with the cabbage. Then he goes back. Next, he takes the cabbage across. Then the man goes back, taking the goat with him. After this, he takes the wolf across. Then he goes back again, leaving the wolf with the cabbage. Finally, he takes the goat across. .
16 :: Its always 1 to 6, its always 15 to 20, its always 5, but its never 21, unless its flying. What is this?
The answer is:
a dice. An explanation: "It's always 1 to 6": the numbers on the faces of the dice, "it's always 15 to 20": the sum of the exposed faces when the dice comes to rest after being thrown, "it's always 5": the number of exposed faces when the dice is at rest, "but it's never 21": the sum of the exposed faces is never 21 when the dice is at rest, "unless it's flying": the sum of all exposed faces when the dice is flying is 21 (1 + 2 + 3 + 4 + 5 + 6)..
a dice. An explanation: "It's always 1 to 6": the numbers on the faces of the dice, "it's always 15 to 20": the sum of the exposed faces when the dice comes to rest after being thrown, "it's always 5": the number of exposed faces when the dice is at rest, "but it's never 21": the sum of the exposed faces is never 21 when the dice is at rest, "unless it's flying": the sum of all exposed faces when the dice is flying is 21 (1 + 2 + 3 + 4 + 5 + 6)..
17 :: Richard is a strange liar. He lies on six days of the week, but on the seventh day he always tells the truth. He made the following statements on three successive days: Day 1: "I lie on Monday and Tuesday." Day 2: "Today, it's Thursday, Saturday, or Sunday." Day 3: "I lie on Wednesday and Friday." On which day does Richard tell the truth?
We know that Richard tells the truth on only a single day of the week. If the statement on day 1 is untrue, this means that he tells the truth on Monday or Tuesday. If the statement on day 3 is untrue, this means that he tells the truth on Wednesday or Friday. Since Richard tells the truth on only one day, these statements cannot both be untrue. So, exactly one of these statements must be true, and the statement on day 2 must be untrue. Assume that the statement on day 1 is true. Then the statement on day 3 must be untrue, from which follows that Richard tells the truth on Wednesday or Friday. So, day 1 is a Wednesday or a Friday. Therefore, day 2 is a Thursday or a Saturday. However, this would imply that the statement on day 2 is true, which is impossible. From this we can conclude that the statement on day 1 must be untrue. This means that Richard told the truth on day 3 and that this day is a Monday or a Tuesday. So day 2 is a Sunday or a Monday. Because the statement on day 2 must be untrue, we can conclude that day 2 is a Monday. So day 3 is a Tuesday. Therefore, the day on which Richard tells the truth is Tuesday. .
18 :: Tom has three boxes with fruits in his barn: one box with apples, one box with pears, and one box with both apples and pears. The boxes have labels that describe the contents, but none of these labels is on the right box. How can Tom, by taking only one piece of fruit from one box, determine what each of the boxes contains?
Tom takes a piece of fruit from the box with the labels 'Apples and Pears'. If it is an apple, then the label 'Apples' belong to this box. The box that said 'Apples', then of course shouldn't be labeled 'Apples and Pears', because that would mean that the box with 'Pears' would have been labeled correctly, and this is contradictory to the fact that none of the labels was correct. On the box with the label 'Appels' should be the label 'Pears'. If Tom would have taken a pear, the reasoning would have been in a similar way. .
19 :: Joyce has bought ten trees for her garden. She wants to plant these trees in five rows, with four trees in each row.
The Question :How must Joyce plant the trees?
The answer to this riddle is to arrange the trees in the shape of a 'star' as illustrated below.
DRAW A STAR TO GET THE ANSWER.
T
T T T T
T T
T
T T
Conventional 'Star drawing' has five lines. These five lines represent the five rows. At each node in the diagram where two 'lines of star' meet a tree can be planted. Thus each of the five rows has four trees.
DRAW A STAR TO GET THE ANSWER.
T
T T T T
T T
T
T T
Conventional 'Star drawing' has five lines. These five lines represent the five rows. At each node in the diagram where two 'lines of star' meet a tree can be planted. Thus each of the five rows has four trees.
20 :: You walk upwards on an escalator, with a speed of 1 step per second. After 50 steps you are at the end. You turn around and run downwards with a speed of 5 steps per second. After 125 steps you are back at the beginning of the escalator. How many steps do you need if the escalator stands still?
Let v be the speed of the escalator, in steps per second. Let L be the number of steps that you need to take when the escalator stands still. Upwards (along with the escalator), you walk 1 step per second. You need 50 steps, so that takes 50 seconds. This gives: L - 50 ?v = 50. Downwards (against the direction of the escalator), you walk 5 steps per second. You need 125 steps, so that takes 25 seconds. This gives: L + 25 ?v = 125. From the two equations follows: L = 100, v = 1. When the escalator stands still, you need 100 steps..
21 :: A number is called a palindrome when it is equal to the number you get when all its digits Postman Pat delivers the mail in the small village Tenhouses. This village, as you already suspected, has only one street with exactly ten houses, numbered from 1 up to and including 10. In a certain week, Pat did not deliver any mail at two houses in the village; at the other houses he delivered mail three times each. Each working day he delivered mail at exactly four houses. The sums of the house numbers where he delivered mail were: on Monday: 18 on Tuesday: 12 on Wednesday: 23 on Thursday: 19 on Friday: 32 op Saturday: 25 on Sunday: he never works Which two houses didn't get any mail that week?
If postman Pat would have delivered mail three times at each house, then the total sum of the house numbers per day would be (1+2+3+4+5+6+7+8+9+10)?=165. Now that sum is 18+12+23+19+32+25=129. The difference is 165-129=36; divided by 3 this is 12. The sum of the house numbers where no mail was delivered is therefore 12. The following combination are possible: 2+10
3+9
4+8
5+7
Each day at four houses the mail was delivered. On Tuesday the sum was 12. 12 can only be made from four house numbers in 2 ways:
1+2+3+6
1+2+4+5
The same holds for Friday with the sum of 32
5+8+9+10
6+7+9+10
From this we can conclude that the house numbers 1, 2, 9 and 10 for sure have received mail, which means that the combination 2+10 and 3+9 are not possible. Also the combination 5+7 is not possible, because mail was delivered either at house 5 or at house 7. Thus the only remaining solution is: houses 4 and 8.
N.B.: there are various possibilities for the actual post delivery of the whole week. For example: Monday houses 1, 3, 5 and 9
Tuesday houses 1, 2, 3 and 6
Wednesday houses 1, 5, 7 and 10
Thursday houses 2, 3, 5 and 9
Friday houses 6, 7, 9 and 10
Saturday houses 2, 6, 7 and 10
3+9
4+8
5+7
Each day at four houses the mail was delivered. On Tuesday the sum was 12. 12 can only be made from four house numbers in 2 ways:
1+2+3+6
1+2+4+5
The same holds for Friday with the sum of 32
5+8+9+10
6+7+9+10
From this we can conclude that the house numbers 1, 2, 9 and 10 for sure have received mail, which means that the combination 2+10 and 3+9 are not possible. Also the combination 5+7 is not possible, because mail was delivered either at house 5 or at house 7. Thus the only remaining solution is: houses 4 and 8.
N.B.: there are various possibilities for the actual post delivery of the whole week. For example: Monday houses 1, 3, 5 and 9
Tuesday houses 1, 2, 3 and 6
Wednesday houses 1, 5, 7 and 10
Thursday houses 2, 3, 5 and 9
Friday houses 6, 7, 9 and 10
Saturday houses 2, 6, 7 and 10
22 :: Two friends, Alex and Bob, go to a bookshop, together with their sons Peter and Tim. All four of them buy some books; each book costs a whole amount in shillings. When they leave the bookshop, they notice that both fathers have spent 21 shillings more than their respective sons. Moreover, each of them paid per book the same amount of shillings as books that he bought. The difference between the number of books of Alex and Peter is five. Who is the father of Tim?
For each father-son couple holds: the father bought x books of x shillings, the son bought y books of y shillings. The difference between their expenses is 21 shillings, thus x2 - y2 = 21. Since x and y are whole numbers (each book costs a whole amount of shillings), there are two possible solutions: (x=5, y=2) or (x=11, y=10). Because the difference between Alex and Peter is 5 books, this means that father Alex bought 5 books and son Peter 10. This means that the other son, Tim, bought 2 books, and that his father is Alex. .
23 :: There is a whole number n for which the following holds: if you put a 4 at the end of n, and multiply the number you get in that way by 4, the result is equal to the number you get if you put a 4 in front of n. In other words, we are looking for the number you can put on the dots in the following equation: 4... = 4 ?...4 Which number must be put on the dots to get a correct equation?
n4*4=4n.
1) if n is single digit number then we get n will be fraction.
2)similarly tru for n as 2,3,4 digit numbers we won't get.
3) let n=abcde
then
abcde4*4=4abcde
which by solving we get 13*abcde=133328
so abcde=10256.
thus 102564*4=410256
1) if n is single digit number then we get n will be fraction.
2)similarly tru for n as 2,3,4 digit numbers we won't get.
3) let n=abcde
then
abcde4*4=4abcde
which by solving we get 13*abcde=133328
so abcde=10256.
thus 102564*4=410256
24 :: The gentlemen Dutch, English, Painter, and Writer are all teachers at the same secondary school. Each teacher teaches two different subjects. Furthermore: Three teachers teach Dutch language There is only one math teacher There are two teachers for chemistry Two teachers, Simon and mister English, teach history Peter does not teach Dutch language Steven is chemistry teacher Mister Dutch doesn't teach any course that is thought by Karl or mister Painter. What is the full name of each teacher and which two subjects does each one teach?
Since Peter as only one doesn't teach Dutch language, and mister Dutch doesn't teach any course that is taught by Karl or mister Painter, it follows that Peter and mister Dutch are the same person and that he is at least math teacher. Simon and mister English both teach history, and are also among the three Dutch teachers. Peter Dutch therefore has to teach next to math, also chemistry. Because Steven is also chemistry teacher, he cannot be mister English or mister Painter, so he must be mister Writer. Since Karl and mister Painter are two different persons, just like Simon and mister English, the names of the other two teachers are Karl English and Simon Painter. Summarized:Peter Dutch, math and chemistrySteven Writer, Dutch and chemistrySimon Painter, Dutch and historyKarl English, Dutch and history..
25 :: Postman Pat delivers the mail in the small village Tenhouses. This village, as you already suspected, has only one street with exactly ten houses, numbered from 1 up to and including 10. In a certain week, Pat did not deliver any mail at two houses in the village; at the other houses he delivered mail three times each. Each working day he delivered mail at exactly four houses. The sums of the house numbers where he delivered mail were: on Monday: 18 on Tuesday: 12 on Wednesday: 23 on Thursday: 19 on Friday: 32 op Saturday: 25 on Sunday: he never works Which two houses did not get any mail that week?
If postman Pat would have delivered mail three times at each house, then the total sum of the house numbers per day would be (1+2+3+4+5+6+7+8+9+10)?=165. Now that sum is 18+12+23+19+32+25=129. The difference is 165-129=36; divided by 3 this is 12. The sum of the house numbers where no mail was delivered is therefore 12. The following combination are possible
2+10
3+9
4+8
5+7
Each day at four houses the mail was delivered. On Tuesday the sum was 12. 12 can only be made from four house numbers in 2 ways:
1+2+3+6
1+2+4+5
The same holds for Friday with the sum of 32:
5+8+9+10
6+7+9+10
From this we can conclude that the house numbers 1, 2, 9 and 10 for sure have received mail, which means that the combination 2+10 and 3+9 are not possible. Also the combination 5+7 is not possible, because mail was delivered either at house 5 or at house 7. Thus the only remaining solution is: houses 4 and 8.
N.B.: there are various possibilities for the actual post delivery of the whole week.
For example: Monday houses 1, 3, 5 and 9
Tuesday houses 1, 2, 3 and 6
Wednesday houses 1, 5, 7 and 10
Thursday houses 2, 3, 5 and 9
Friday houses 6, 7, 9 and 10
Saturday houses 2, 6, 7 and 10 .
2+10
3+9
4+8
5+7
Each day at four houses the mail was delivered. On Tuesday the sum was 12. 12 can only be made from four house numbers in 2 ways:
1+2+3+6
1+2+4+5
The same holds for Friday with the sum of 32:
5+8+9+10
6+7+9+10
From this we can conclude that the house numbers 1, 2, 9 and 10 for sure have received mail, which means that the combination 2+10 and 3+9 are not possible. Also the combination 5+7 is not possible, because mail was delivered either at house 5 or at house 7. Thus the only remaining solution is: houses 4 and 8.
N.B.: there are various possibilities for the actual post delivery of the whole week.
For example: Monday houses 1, 3, 5 and 9
Tuesday houses 1, 2, 3 and 6
Wednesday houses 1, 5, 7 and 10
Thursday houses 2, 3, 5 and 9
Friday houses 6, 7, 9 and 10
Saturday houses 2, 6, 7 and 10 .
