suppose a runner completes a 10k road race in 41 minutes and 23 seconds. What is the runner's average speed in miles per hour?

To answer this, convert 41 minutes to seconds and add 23 seconds to that, then divide by 60 to convert to hours.

41 min = 2460 seconds (+ 23 seconds) = 2483 / 60 = 41.383 minutes (0.68972 hours).

Speed = 10km/0.68972 hr = 14.498/hr

14.498 kilometers = 9.008 miles.

So the runner's average speed is roughly 9 miles per hour.

An easy way to remember the distance, speed and time equations is to put the letters into a triangle. See illustration on the side.

The triangles will help you remember these 3 rules:

Distance = Speed x Time

Time = Distance/Speed

Speed= Distance/Time

Use this Speed Distance Time Calculators to work out the calculations easily.