Speed of boat with no current --- x mph
speed of current ----- y mph
Assuming 16 miles each way,
time with the current = 1 hr
16/(x+y) = 1
x+y = 16 ----> #1
time against the current = 9 hrs
16/(x-y) = 9
9x - 9y = 16----> 2
you now have two simple equations in 2 unknowns
Use your usual method solving these equations.
Hint: the speeds are not whole numbers
Suppose a boat has to make a round trip up and down a river. The trip up takes 1 hour and is with the current. The trip back takes 9 hours. Suppose the round trip is a total of 32 miles, and that the boat's speed and the speed of the current are constant. What is the boat's speed and what is the current's speed?
1 answer
1 answer