SOLUTION: 84.)Gone Fishing. Debbie traveled by boat 5 miles upstream to fish in her favorite spot. Because of the 4 - mph current, it took her 20 minutes longer to get there than to return.
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Question 166418: 84.)Gone Fishing. Debbie traveled by boat 5 miles upstream to fish in her favorite spot. Because of the 4 - mph current, it took her 20 minutes longer to get there than to return. how fast will her boat go in still water? Answer by Alan3354(69443) (Show Source):
You can put this solution on YOUR website! 84.)Gone Fishing. Debbie traveled by boat 5 miles upstream to fish in her favorite spot. Because of the 4 - mph current, it took her 20 minutes longer to get there than to return. how fast will her boat go in still water?
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time = distance/speed
time upstream = 5/(b - 4) b is the boat's speed
time downstream = 5/(b+4) = time upstream - 1/3 (20 mins is 1/3 hours)
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5/(b+4) = 5/(b-4) - 1/3
Multiply by 3*(b+4)*(b-4)
15*(b-4) = 15*(b+4) - b^2 + 16
15b-60 = 15b+ 60 -b^2 + 16
-60 = 76 - b^2
b^2 = 136
b = 11.66 mph
