What is the binary number system primarily used for in

UDGO : FWTL : : MXRC : ?

Select the missing number from the given responses.

Find the missing number?

Study the given pattern carefully and select the number that can replace the question mark (?) in it.

First row: 14, 17, 40

Find the missing number.

What number should replace the question mark? 

Find the missing term in the given series:

In each of the following questions, select the related number from the given alternatives:

8/15 : 2/5 : : 16/21 : ?

Select the related number from the given alternatives.

29 : 65 : : 43 : ?

Find the missing numbers.