Don Williams uses his small motorboat to go 5 miles upstream to his favorite fishing spot. Against the current, the trip takes 1/3 hour. With the current the trip takes 1/5 hour. How fast can the boat travel in still water?
Suppose x is the rate at which the boat travels at still water. let y be rate in moving water up stream is x-y down stream is x+y the 1/3(x-y)=5 1/5(x+y)=5 solve the system x-y=15 x+y=25 add the equation to cancel y we get 2x=40 x=20 therefore the boat is moving at rate of 20 miles for hour in still water
