Question

Hemant and Ajay start a two-length swimming race at the same moment but from opposite ends of the pool. They swim in the lane and at a uniform speed, but Hemant is faster than Ajay. They first pass at a point 18.5 m from the deep end and having completed one length, each one is allowed to rest on the edge for exactly 45 seconds.After setting off on the return length, the swimmers pass for the second time just 10.5 m from the shallow end.How long is the pool?

Answer 1

Let length of the pool be L.

Deep

A —————————————><———————————----———————————— H

.................(18.5m)

H ——————————————————————————-———><————————- A

..............................................................................................................(10.5)

In same time, Andy covers 18.5 and Hardy covers L - 18.5.

In same time, Andy covers L - 18.5 + 10.5 while Hardy covers 18.5 + L - 10.5

The ratio of these distances covered would be the same since the speeds of both people are constant.

18.5/(L - 18.5) = (L - 8)/(L + 8)

Plug in the options to find that L = 45 works.