Races and Games - General Questions

In a 100 m race, A beats B by 25 m and B beats C by 40 m. By how many metres does A beat C?

In a 200 m race, A beats B by 40 m and B beats C by 10 m. By how many metres does A beat C?

A runs 1 1/7 times as fast as B. If A gives B a start of x metres so that the race of 200 m ends in a dead heat, what is x?

A runs 1 1/3 times as fast as B. If A gives B a start of x metres so that the race of 300 m ends in a dead heat, what is x?

A can run 200 m in 16 seconds and B in 20 seconds. By how many metres does A beat B?