Let us first try to define analogy: the word  'Analogy' means 'correspondence’. In analogy questions, a specific relationship is given & another similar relationship has to be identified from the given options.

In reasoning, generally we come across two  types of analogies: Alphabet analogy and Numbers analogy.

Number Analogy covers two types of questions:

I. Choose a similar pair as the given pair in the question on the basis of the relation between the numbers pair given in the question.

II. Choose a number that is similar to a group of numbers on the basis of certain similar properties that they possess.

Example: Find a pair that is similar to the given pair of numbers:- 180:90

Sol.: Clearly, the relationship here is 2x : x.

This same relationship exists in option (b).

So, the correct answer is option (b).

Alphabet Analogy: In this type of analogy, two groups of letters related to each other in same way, are given. The candidate is required to identify the relationship & choose a group of letters which is related in the same way to a 3rd group given in the question. These questions become easier to solve if you memorize the alphabetic positions of the letters in the alphabet. (eg: A=1, M=13, etc.)

Example: BCDE: PQRS :: WXYZ : ?

Sol. Each letter of the 1st group is moved 14 steps forward to obtain the corresponding letter of the 2nd group. A similar relationship will exist between the 3rd and 4th groups.

Hence, the correct answer is option (b).

Now that we have gone through the basics of analogy, let us study a few analogy examples click here