A can give B a 200 m start up and C a 300 m start up in a race of 1 km

SOLUTION

Ratio of speeds of A : B = 1000 : 800 = 5 : 4

Ratio of speeds of A : C = 1000 : 700 = 10 : 7

Ratio of speeds of B : C = 800 : 700 = 8 : 7

Since, when B moves 8 m, C moves 7 metre. Therefore, when B moves 1000 m, C moves 875 metre. Thus B can give C a start of 1000 – 875 = 125 m

Alternatively : Since C is 12.5% slower than B. so, C will cover 12.5% less distance than B in the same time.

(since when time is constant, they cover the distances in the ratio of their speeds.)

Thus, in 1000 m (or 1 km) when B runs 1000 m, C will run 125 m less than B

Hence, B can give a start of 125 m to C in a 1 km race.