Answers

2014-05-08T08:22:38+05:30
In 40 sec he completes 1 round.
in 80 sec he completes 2 round
so in 2min 20sec he will complete 2 1/2 rounds
so his displacement is 20 m

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2014-05-09T09:44:20+05:30
Displacement is 3 and 1/2 round 
2 min 20 s - 140 s 
10 m - 40 s
140 s - 3 1/2 rounds
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