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Two boys, A and B, runs at 41⁄2 and 6 Km an hour. A having 190 m start. The course being 1 Km, B wins by a distance of :
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- 60 m
- 65 m
- 45 m
- 75 m
Correct Option: A
Speeds (in m/sec) of A and B are
9 / 2 * 5 / 18 = 5 / 4 and 6 * 5 / 18 = 5 / 3, respectively.
A has a start of 190 m.
So, A has to run 1000 - 190 = 810 m, while B 1000 m.
Time taken by B to cover 1000 m = 3 5 × 1000 = 600 seconds.
In this time, A covers 5 × 600 / 4 = 750 m.
So, B reaches the winning post while A remains 810 - 750 = 60 m behind.
∴ B wins by 60 m.
