SOLUTION: can you please help me!!!!!!! solve this one using Rational expression!!!! Debbie traveled by boat 5 miles upstream to fish in her favorite spot. because of the 6-mph current, it t

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Question 36772: can you please help me!!!!!!! solve this one using Rational expression!!!! Debbie traveled by boat 5 miles upstream to fish in her favorite spot. because of the 6-mph current, it took her 20 minutes longer to get there than to return. How fast will her boat go in still water? (please round your answer to one decimal place)
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
Debbie traveled by boat 5 miles upstream to fish in her favorite spot. because of the 6-mph current, it took her 20 minutes longer to get there than to return. How fast will her boat go in still water? (please round your answer to one decimal place)
Upstream Data:
distance=5miles; rate=boat speed - current= b-6 mph; time=5/(b-6)
Downstream Data:
distance=5mils; rate=boat speed + current= b+6 mph; time= 5/(b+6)
EQUATION:
Upstream time - (1/3)hr = Downstream time
5/(b-6)- (1/3)=5/(b+6)
5(3)(b+6)-(b+6)(b-6)=5(3)(b-6)
15b+90-[b^2-36]=15b-90
b^2-216=0
b=14.697mph
boatspeed in still water is 14.697mph
Cheers,
Stan H.