SOLUTION: It took a crew 3 h 45 min to row 9 km upstream and back again. If the rate of flow of the stream was 1 km/h, what was the rowing speed of the crew in still water?
I got to 5x^2-
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Question 1046197: It took a crew 3 h 45 min to row 9 km upstream and back again. If the rate of flow of the stream was 1 km/h, what was the rowing speed of the crew in still water?
I got to 5x^2-24x-5=0
Answer by jorel555(1290) (Show Source): You can put this solution on YOUR website!
Let x be the rowing speed of the crew. Then:
9/(x+1)+9/(x-1)=3.75
9(x-1)+9(x+1)=3.75x²-3.75
36x-36+36x+36=15x²-15
15x²-72x-15=0
(15x+3)(x-5)=0
x=-3/15,5
Throwing out the negative result, the rowing speed of the crew in still water was 5 kph. ☺☺☺☺
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