In the following number-pairs, the second number is obtained by applying certain mathematical operation(s) to the first number. Select the number-pair in which the numbers are related in the same way as are the numbers of the following pairs.
(NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into their constituent digits. E.g. 13 – Operations on 13 such as adding to/subtracting from/multiplying with 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)
18, 141
42, 165

Correct option is A

Logic:
The relationship between the numbers is based on a constant difference.
Second number−First number=123

Explanation:
141−18=123
165−42=123
Hence, the same difference of 123 should apply to the correct pair.

For option (a):
159−36=123
 Therefore, the logic is Difference = 123.

Final Answer: (a) 36, 159