<PRE><B>Question 388652</B>
A motorboat can go 16 miles downstream on a river in 20 minutes. It takes 30 minutes for this boat to go back upstream the same 16 miles.Let x = the speed of the boat.
Let y = the speed of the current.


a. Write an equation for the motion of the motorboat downstream.
d = 48t, d in miles, t in hours
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b. Write an equation for the motion of the motorboat upstream.
d = 32t, d in miles, t in hours
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c. Find the speed of the current. 
y = 8 mph
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16 miles in 20 mins = 48 mph
16 miles in 30 mins = 32 mph
The boat speed is the average = (48 + 32)/2 = 40 mph
The current is the difference = 8 mph
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