If a swimmer swam five miles in 34.7 minutes, what's his speed in meters per second?

To get the speed in m/s, you need to take the total distance in meters and divide by the total time in seconds.

So you need to figure out how many meters are in five miles; then you need to figure out how many seconds are in 34.7 minutes.

Let's do the second part first: How many seconds are in a minute? 60, of course. So how many seconds in 34.7 minutes? 34.7 * 60 = 2082 seconds.

Likewise for the distance. How many meters are in 1 mile? If you don't know, I'm sure your textbook has the answer, or you can find the answer with Google in a matter of seconds. Once you know how many meters are in 1 mile, it's pretty obvious that there are 5 times as many meters in 5 miles.

That's all there is to it.