SOLUTION: A motorboat has a four-hour supply of gasoline. How far from the marina can it travel if the rate going out against the current is 20 mi/h and the rate coming back with the curren

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Question 365519: A motorboat has a four-hour supply of gasoline. How far from the marina can it travel if the rate going out against the current is 20 mi/h and the rate coming back with the current is 30 mi/h?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
A motorboat has a four-hour supply of gasoline.
How far from the marina can it travel if the rate going out against the
current is 20 mi/h and the rate coming back with the current is 30 mi/h?
:
Let d = the one-way distance (dist from marina)
Write a time equation: time = dist/speed
:
out time + return time = 4 hrs
d%2F20 + d%2F30 = 4
multiply by 60, to clear the denominators, results:
3d + 2d = 60(4)
5d = 240
d = 240%2F5
d = 48 miles
:
:
see if that's true, find the time each way
48/20 = 2.4 hrs
48/30 = 1.6 hrs
----------------
totals: 4.0 hrs; confirms our solution of 48 mi