SOLUTION: A pump boat moves at an average speed of 40 kilometers per hour. Suppose it can cover a certain distance in 2hours. if it is moving in the direction of the current and in 2 1/2 hou

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Question 551669: A pump boat moves at an average speed of 40 kilometers per hour. Suppose it can cover a certain distance in 2hours. if it is moving in the direction of the current and in 2 1/2 hours if it is moving against the current. What is the speed of the current?
Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website!
Boat speed = 40 km/h
current speed = x km/h
wind speed
speed against current 40 -x
speed with current 40 +x

Distance against current x km
Distance with current x km
time with current = 2 hours
y/(40+x) =2
y=2(40+x)
y=80+2x..........(1)
Time against current = 2 1/2 hours
y/(40-x)=5/2
y= 5(40-x)/2............(2)
equate equation (1) & (2)
80+2x=5(40-x)/2
multiply by 2
160+4x=200-5x
9x=40
/9
x=40/9
x=4.44 km/h speed of current
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