A walks at 4 kmph and 4 hours after his start, B cycles after him at 10 kmph. How far from the start does B catch up with A?	Choices: A) 62.6 km B) 26.7 km C) 22.8 km D) 19.5 km E) None
Sol.   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 4 hours.   ∴ x/4 - x/10 = 4 or x = 26.7 km.   Answer 26.7 km
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A walks at 4 kmph and 4 hours after his start, B cycles after him at 10 kmph. How far from the start does B catch up with A?