SOLUTION: A certain river has a speed of 2.50 mi/h. A rower travels downstream for 1.50 h and returns in 4.50 h. Find his rate in still water, and find the one-way distance traveled.

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Question 701699: A certain river has a speed of 2.50 mi/h. A rower travels downstream for
1.50 h and returns in 4.50 h. Find his rate in still water, and find the one-way
distance traveled.
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
Fundamental relationship is speed multiplied by time equals distance, r*t=D
Let r equal rower's speed if in still water.
Let D equal the one way distance.

Use this format if building a table of data....
Direction: Speed-----------Time---------Distance
Downstream: r+2.5 ---------1.5 ---------D=(r+2.5)(1.5)
Upstream: r-2.5 ----------4.5 ---------D=(r-2.5)(4.5)

Up and downstream were the same distance, just different rates, so equate the expressions for D:

%28r%2B2.5%29%2A1.5=%28r-2.5%29%2A4.5
Divide both sides by 1.5,
r%2B2.5=3%2A%28r-2.5%29
r%2B2.5=3%2Ar-7.5
2.5%2B7.5=2r
r=5
In still water, the rower's speed is 5 miles per hour.
You can finish by choosing either formula for D to compute the one way distance.