(21 - 6) , (28 - 42) , (42 - 12) , (84 -24) - Choose odd Number Pair / Group - Classification

Choose or find odd number pair

(21 - 6) , (28 - 42) , (42 - 12) , (84 -24)

A. 21 - 6

B. 28 - 42

C. 42 - 12

D. 84 -24

Answer: B . 28 - 42

Justification: In all other pairs, 1st number = 2nd number × 7/2