In a 500 m race, the speeds of A and B are in the ratio 3 : 4. A is given a start of 140 m. Who wins, and by how much?

Explanation

1. 01

   A has $500 - 140 = 360$ m to run. In that time B runs $\frac{4}{3} \times 360 = 480$ m.

2. 02

   B is still 20 m short when A finishes, so A wins by 20 m.