SOLUTION: A motorboat maintained a constant speed of 12 miles per hour relative to the water in going 45 miles upstream and then returning. the total time for the trip was 8.0 hours. Use thi
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Question 907271: A motorboat maintained a constant speed of 12 miles per hour relative to the water in going 45 miles upstream and then returning. the total time for the trip was 8.0 hours. Use this information to find the speed of the current Answer by richwmiller(17219) (Show Source):
You can put this solution on YOUR website! r*t=d
t=d/r
d/r+d/r=t
45/(12-c)+45/(12+c)=8
(12-c)*(12+c)=(144-c^2)
45*(12+c)/(144-c^2))+45*(12-c)/(144-c^2)=8
(540+45*c)+540-45*c))/(144-c^2)=8
(540+540)/(144-c^2)=8
(1080)/(144-c^2)=8
1080=8*(144-c^2)
135=144-c^2
135-144=-c^2
-9=-c^2
c^2=9
c=+-3.0
