In a 500 metres race, B starts 45 metres ahead of A

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?

1. 25:20
2. 25:21
3. 5:7
4. 5:3