Maths
Answers (1)
Average speed is distance divided by time. But you want to convert the units to m/s.
A conversion factor is a fraction equal to 1. You are given that one minute equals 60 seconds so you can write that as min/60s=1 or 60s/min=1 whichever works for you and drop it into an equation anywhere and it only changes the units.
ANSWER = You write this first so it looks like you know what you are doing. That gives you a bit of time to figure out what to do next.
ANSWER = 7.5km/27.5min x 1000m/km x min/60s
Ok, now we check everything. This is called sanity check and it is especially important in chemistry and physics where you might have a dozen or so conversions in a single equation. We have km on top and again on bottom, so that cancels. Min on bottom and min on top cancels. m on top and s on bottom appear in the answer like we want them. When you are sure everything is right, multiply all the numbers on top and divide by all the numbers on bottom.
ANSWER = 7.5km/27.5min x 1000m/km x min/60s = 4.545454 m/s