Linux General Question:

rpm is packagemanager while yum is a frontend,rpm can be
installed with the help of yum

RPM Package Manager” (formerly “Red Hat Package Manager”),
and YUM, “Yellow dog Updater,
Package Management System Installer
Typically part of the operating system. Each product comes
bundled with its own installer.
Uses a single installation database. Performs its own
installation, sometimes recording information about that
installation in a registry.
Can verify and manage all packages on the system. Only works
with its bundled product.
Single package management system vendor. Multiple installer
vendors.
Single package format. Multiple installation formats.