SOLUTION: a man swimming in a river finds that it takes him thrice the time to swim 2km upstream as it takes him to swim back.if the river flows at the rate of 1.5 km/hr find the swimming sp

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: a man swimming in a river finds that it takes him thrice the time to swim 2km upstream as it takes him to swim back.if the river flows at the rate of 1.5 km/hr find the swimming sp      Log On


   



Question 313348: a man swimming in a river finds that it takes him thrice the time to swim 2km upstream as it takes him to swim back.if the river flows at the rate of 1.5 km/hr find the swimming speed of the man in still water
Answer by mananth(16946) About Me  (Show Source):
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a man swimming in a river finds that it takes him thrice the time to swim 2km upstream as it takes him to swim back.if the river flows at the rate of 1.5 km/hr find the swimming speed of the man in still water
..
let the speed in still water be x km/hr.
upstream the speed will be x-1.5
distance = 2km
time taken upstream = 2/(x-1.5)
..
downstream speed = x+1.5
distance = 2km
time taken = 2/(x+1.5)
..
he takes thrice the time upstream.
2/(x-1.5) = 3*(2/x+1.5)
(x+1.5)(x-1.5)=3
x^2-2.25=3
x^2= 0.75
=0.87 km/hr