The ratio of speed of A and B is 3 : 7 and A loses the race by 360 m, then find the length of the race.

630 m 420 m 510 m 560 m

630 m

The time is same for A and B.  Therefore, Distance ∝ Speed,                   A          :           B Speed         3          :           7 Distance      3          :           7          Difference = 4R 4R = 360 1R = 90 The length of race = distance covered by B = 7 × 90 = 630 m