In a 500 m race, A beats B by 20 m and C by 80 m. If B and C run another race of 100 m with exactly the same speed as before, then by how many metres will B beat C?

A10.0 m

B8.5 m

C15.0 m

D12.5 m ✓ Correct

Correct answer: (D) 12.5 m

Explanation

B beats C by 12.5 m.

When A runs 500 m, B runs 480 m and C runs 420 m.

So B to C speed ratio = 480 : 420 = 8 : 7.

In 100 m, when B runs 100, C runs 100 x 7/8 = 87.5 m.

B beats C by 100 - 87.5 = 12.5 m.

Want more like this? Create a free account to practise a full test, track your progress, and get spaced-repetition review.