Problema Solution
A boy can row a boat at a constant rate of 5 mi/hr in still water, as indicated in the figure. He rows upstream for 21 minutes and then rows downstream, returning to his starting point in another 14 minutes
Answer provided by our tutors
we assume that this problem is asking for the speed of the current
let 'v' represent the speed of the current, then '5+v' represents downstream speed and '5-v' represents upstream speed
14 minutes = 14/60 hours
21 minutes = 14/60 hours
distance = speed * rate
the distance is the same in both cases, so we set the speed*rate expressions equal to each other
(5+v)(14/60) = (5-v)(21/60)
solving for 'v' we have v=1
the speed of the current is 1mph