Three of the following four options are alike in a certain way and thus form a group. Which is the one that does NOT belong to that group?
(NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into their constituent digits. For example, 13 – Operations on 13, such as addition, subtraction, multiplication, etc., 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 – 122 – 99.
Logic: 1st number × 2 + 3rd number = 2nd number.
1) 12 – 122 – 99 → 12 × 2 + 99 = 24 + 99 = 123 ≠ 122
2) 89 – 212 – 34 → 89 × 2 + 34 = 178 + 34 = 212
3) 23 – 84 – 38 → 23 × 2 + 38 = 46 + 38 = 84
4) 58 – 139 – 23 → 58 × 2 + 23 = 116 + 23 = 139