Three of the following number-pairs are alike in some manner and hence form a group. Which number-pair does not belong to that group?
(NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E.g. 13 – Operations on 13 such as adding/subtracting/multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 12 – 225.
Option 1) 12 – 225 → (12 + 2)2 = 196 ≠ 225
Option 2) 8 – 100 → (8 + 2)2 = 100
Option 3) 9 – 121 → (9 + 2)2 = 121
Option 4) 6 – 64 → (6 + 2)2 = 64