Question 887104:  The first cyclist leaves point A and averages 10km/h . 30 minutes later a second cyclist leaves point A and averages 15 km/hour . How many minutes till he catches up to the first cyclist ? And how many km did it take to catch up ? 
 Answer by JulietG(1812)      (Show Source): 
You can  put this solution on YOUR website! After 30 minutes, A = 5, B = 0 
After 1 hour, A = 10, B = 7.5 (half of 15kmh since he left 30 mins later) 
After 90 minutes, A = 15, B = 15 
B catches up with A 90 minutes after A leaves (60 minutes after B leaves) at the distance of 15km. 
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