A can run 500m in 30 seconds and B in 35 seconds. How many meter start can A give to B in a Km race so that the race may end in a dead-heat?

Time taken by A to run 1 Km = 30 × 2 = 60 seconds.
Time taken by B to run 1 Km = 35 × 2 = 70 seconds.
∴ A can give B a start of (70 - 60) = 10 seconds.
In 35 sec B runs 500 m
∴ In 10 sec B runs = 500 × 10 / 35 = 1000 / 7 = 142⁶⁄₇ meters
So, A can give B a start of 142⁶⁄₇ meters in a Km race.