Find the odd number pair from the given alternatives.

Concept

In an odd-one-out number-pair question, find the single arithmetic relationship (here, the ratio between the two numbers) that most of the pairs share. The one pair that breaks this common relationship is the odd pair.

Application

Reduce each pair to its simplest ratio:

1. 28 : 8 divides by 4 to give 7 : 2.

2. 84 : 24 divides by 12 to give 7 : 2.

3. 49 : 14 divides by 7 to give 7 : 2.

4. 42 : 6 divides by 6 to give 7 : 1.

Cross-check

Three pairs reduce to the ratio 7 : 2, while 42 : 6 reduces to 7 : 1. Since 42 : 6 is the only pair not in the ratio 7 : 2, it is the odd pair.