The number of products that can be formed with 10 prime numbers taking two or more at a time is

The number of products that can be formed with 8 prime numbers is

A prime number can be even?

What is the number of signals that can be sent by 6 flage of different colour taking one or more at a time ?

The number of signals that can be sent by 5 flags of different colours, taking one or more at a time is :

The number of signals that can be sent by 5 flags of different colours, taking one or more at a time is :

If the sum of three numbers is 10 and the sum of their squares is 38, find the sum of the products of the three numbers taking two at a time.

The number of signals, that can be sent by 5 flags of different colours , taking one or more at a time is :