Question 1180881
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The upstream speed is the rate of the boat MINUS the speed of the current; the downstream speed is the rate of the boat PLUS the speed of the current.<br>
The upstream speed is 18/6=3mph; the downstream speed is 10/2=5mph.<br>
That means the rate of the boat is 4mph and the speed of the current is 1mph.<br>
The information that the boat speed is 4 times the speed of the current is not needed in the problem.<br>