A walks at 30 kmph and 30 hours after his start, B cycles after him at 42 kmph. How far from the start does B catch up with A?
Choose the correct choice from the following.
A) 1200km B) 1500km C) 2000km D) 2500km E) 3150km
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 30 hours.   x/30 - x/42 = 30   x = 3150 km   Answer is 3150km
<result>E</result>
A walks at 30 kmph and 30 hours after his start, B cycles after him at 42 kmph. How far from the start does B catch up with A?