Answers

2014-12-12T23:13:55+08:00
Let 'x' be the speed of boat in still water
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x - 6mph = 70mi/4hr
x - 6mph = 17.5 mph
x = 17.5 + 6 
x = 23.5 mph
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Therefore the boat has a speed of 23.5mph in still water.
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