Hi, new here. I got a question here that I do not understand how to do at all. It'd be nice if someone explained how to solve it.
It took a crew 80 minutes to row 3km upstream and back again. If the rate of the flow of the stream was 3km/h, what was the rowing rate of the crew.
I was going to solve by substitution but I realized that 1.33 cannot be the time for both going up and downstream.
Since we do not know the time taken to row upstream and downstream separately, let " " be the time taken to row upstream and let " " be the time taken to row downstream. Let "v" be their speed in still water.
Then their speed upstream is and that equals "distance divided by time: .
Their speed downstream is and so .
Those, together with give three equations to solve for the three values , , and v. Of course, you are only asked for v so if you could find a way to eliminate and , reducing to a single equation in v, that would be excellent.