In a 500 metres race, B starts 45 metres ahead of A, but A wins the race while B is still 35 metres behind. What is the ratio of the speeds of A to B assuming that both start at the same time?
When A completes and wins the race, at that time B covers 500 - (45 + 35) = 420 metres.
Hence, the ratio between A and B is 500 : 420 = 25 : 21 and this is ratio of speeds of A to B.
The correct option is B.