A walks at 10 kmph and 5 hours after his start, B cycles after him at 20 kmph. How far from the start does B catch up with A?  Pick one:	A) 100km	B) 150km	C) 50km	D) 120km	E) 200km
Suppose after x km from the start B catches up with A. Then, the difference in the time taken by A to cover x km and that taken by B to cover x km is 5 hours.   x/10 - x/20 = 5   x = 100 km   100kmnswer is 100km
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A walks at 10 kmph and 5 hours after his start, B cycles after him at 20 kmph. How far from the start does B catch up with A?