12. | A runs 1 times as fast as B. If A gives B a start of 80 m, how far must the winning post be so that A and B might reach it at the same time? | ||||||||||||||||||

Thus, in race of 5 m, A gains 2 m over B. 2 m are gained by A in a race of 5 m.
Winning post is 200 m away from the starting point. |

13. | In a 100 m race, A can beat B by 25 m and B can beat C by 4 m. In the same race, A can beat C by: | |||||||||||||||||||||||||||

A : B = 100 : 75 B : C = 100 : 96.
A beats C by (100 – 72) m = 28 m. |