Question 500240: Rowan can row 26km downstream in 2 hours. Returning upstream it takes 4 hours to complete the trip. Find his rate in still water and the rate of the current.
Answer by geetha_rama(94)   (Show Source):
You can put this solution on YOUR website! Let b be the speed of the boat in still watetr and c be the rate of the current.
Using the formula, distance = speed * time
In dowmstream
26 = (speed of boat + speed of current) * t
26 = (b + c) * 2
=> b+c = 13 -> equation 1
In upstream,
26 = (speed of boat - spead of current) * t
26 = (b - c ) * 4
=> b -c = 6.5 -> equation 2
eqution 1 - equation 2
2b = 19.5
=> b = 9.75 km/hr
speaad of boat in still water = 9.75km/hr
c = 13 - b ( from eqiation 1)
c= 13 - 9.75
= 3.25 km/hr
=> Speed of current = 3.25km/hr
Check:
b+c = 13 (equation 1)
9.75 + 3.25 = 13
b-c = 6.5 (equation 2)
9.75 - 3.25 = 6.5
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