Question 981261
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n=normal speed(no wind)
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time with wind:
t(with)=75/(n+5mph)
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time against wind:
t(against)=45/(n-5mph)
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Since t(with)=t(against):
75/(n+5mph)=45/(n-5mph)  Cross multiply.
75(n-5mph)=45(n+5mph)
75n-375=45n+225 Subtract 45n from each side.
30n-375=225 Add 375 to each side.
30n=600 Divide each side by 30.
n=20 ANSWER: Jaime's normal rowing speed with no wind is 20 mph.
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CHECK:
n=20 mph
75mi/(n+5mph)=45mi/(n-5mph)
75mi/(20mph+5mph)=45mi/(20mph-5mph)
75mi/25mph=45mi/15mph
3 hrs=3 hrs