A runs 1 2/ 3 times as fast as B. If A gives B a start of 40 m, how far must the winning post be, so that A and B might reach it at the same time?

Ratio of the speeds of A and B = 5 : 3
Thus, in a race of 5m, A gains 2 m over B.
2 m are gained by A in a race of 5 m.
40 m will be gained by A in a race of (5/2) x 40 m = 100 m
∴ Winning post is 100 m away from the starting point.