Find the odd pair/group A. 66-70 B. 30-48 C. 80-98 D. 40-58 E. 72-90 Choose…

Concept: In an 'odd one out' pair/series, each pair is built by the SAME hidden arithmetic rule that ties its two numbers together. Identify the rule that holds for the majority of pairs; the single pair that breaks that rule is the odd one out.

Application: Compute the gap (second number minus first number) for each pair labelled in the stem:

1. 66 to 70: 70 - 66 = 4

2. 30 to 48: 48 - 30 = 18

3. 80 to 98: 98 - 80 = 18

4. 40 to 58: 58 - 40 = 18

5. 72 to 90: 90 - 72 = 18

Four of the five pairs share the rule 'first number + 18 = second number'. Only the 66-70 pair adds 4, so it alone breaks the common rule and is the odd one out.

Cross-check: Re-add 18 to each of the four matching pairs (30+18=48, 80+18=98, 40+18=58, 72+18=90) - all confirm. 66+18 would give 84, not 70, so 66-70 cannot belong to the same family. Hence the correct choice is the one that singles out only the 66-70 pair.