Problema Solution
A boat travels at a constant speed of 20 mph, relative to the water, as it makes a trip downstream and then returns. If the initial trip downstream takes the boat 30 minutes and the return trip upstream takes the boat 40 minutes, what is the speed of the current?
Answer provided by our tutors
let 's' represent the speed of the current
distance = speed * time
distance is the same in both trips, so we set the speed*time expressions equal to each other:
(20+s)(30/60) = (20-s)(40/60)
solving for 's' we have s=2.86
the speed of the current is approximately 2.86mph