Question 1055868

A boat's crew rowed 35 kilometers downstream, with the current, 5 hours. The return trip upstream, against the current, covered the same distance, but took 7 hours. Find the crew's rowing rate in still water and the rate of the current.

The crew's rowing rate in still water is_______ Kilometer(s) per hour.
<pre>Let speed in still water, and of current be S, and C, respectively
Then average speed with the current = {{{35/5}}}, or 7 km/h
Average speed against the current = {{{35/7}}}, or 5 km/h
We then get the following system of AVERAGE-SPEED equations: {{{system(S + C = 7, S - C = 5)}}}
Add the 2 equations to get: 2S = 12
S, or speed in still water = {{{highlight_green(matrix(1,4, 12/2, or, 6, "km/h"))}}}