SOLUTION: A motorboat can travel upstream on a river at 12 mph and downstream at 20 mph. How far upstream can the boat travel if it leaves at 8:00 am and must return by noon?

Question 351783: A motorboat can travel upstream on a river at 12 mph and downstream at 20 mph. How far upstream can the boat travel if it leaves at 8:00 am and must return by noon?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
A motorboat can travel upstream on a river at 12 mph and downstream at 20 mph.
How far upstream can the boat travel if it leaves at 8:00 am and must return by noon?
:
From the information given we know we have to complete the round trip in 4 hrs
:
Let d = one way distance
:
Write a time equation: time = dist/speed
:
Time up + time down = 4 hrs
+ = 4
Clear the denominators multiply by 60
60* + 60* = 60(4)
Cancel the denominators and you have:
5d + 3d = 240
8d = 240
d =
d = 30 miles up-stream to return at noon
:
:
Confirm this, find the times
+ =
2.5 + 1.5 = 4hrs
:
That was pretty easy, right?

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