Number analogy section deals with two types of questions:
I. Choosing a similarly related pair as the given number pair on the basis of the relation between the numbers in each pair.
II. Choosing a number similar to a group of numbers on the basis of certain common properties that they possess.

number analogy

Which number is like the given set of numbers ?
Give set : (3,17,31)

A. 5
B. 15
C. 45
D. 49
Answer: A . 5


Clearly, the numbers in the given set are all prime numbers.
5 is also a prime number and so belong to the same group.
Hence, the answer is (a).