Question

a boy swims down stream at 0.9 miles in the same amount of time that he can swim 0.6 miles up stream. if the rate of the current is 1.5 mph, how fast can he swim in the water?

Answer 1

Let s be the boy's swim speed. Then:
.9/s+1.5=.6/s-1.5
.6s+.9=.9s-1.35
.3s=2.25
s=7.5 mph as the boy's swimming speed
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