In a 1 km race A beats B by 50 m, and in another 1 km race B beats C by 40 m. By how many metres does A beat C in a 1 km race?

Explanation

1. 01

   When A runs 1,000 m, B runs 950 m, and C runs $950 \times \frac{960}{1{,}000} = 912$ m.

2. 02

   A beats C by $1{,}000 - 912 = 88$ m.