Explanation : When A has run 250 yards, B should have run
550 - 250 = 300 yards.
∴ Bruns 300 - 100 = 200 yards in the same time
taken by A to run 250 yards.
∴ Ratio of the speeds of A and B
= 250 : 200 = 5 : 4
If speed of A is 5x yards per minute, then speed
at B = 4x yards/min.
Time taken by B to reach the starting point
Hence B is 10 yards behind A.