Walking in kilometers

Yesterday, it was raining. Umbrellas slowed our walk. It took us 36 minutes to walk 4 kilometers, but these numbers should make computation easy. What was our speed in kilometers per hour?

Hint: convert 36 minutes to fraction of an hour, then divide 4 kilometers by this fraction to get kilometers per hour. Dividing by a fraction divides the mathematicians from the non-mathematicians, so if you have any trouble, let me know.

Answer: Between VI and VII kilometers per hour.

In new Minnesota Science standards, all computations are in meters, kilograms and seconds. What was our speed in meters per second? Hint: convert 4 kilometers to 4000 meters and 36 minutes to seconds, then divide. You will get an answer that is roughly 2 meters per second.

This is advanced, but the exact answer is 50/27 meters per second. 50/27 has a repeating decimal expansion, 1.851 851 851 you can write as 1.851 with a bar over the "851"

You could lay out 2 meters on the ground and see if you can walk that far in a second. Elementary-school students may need to jog. Start on two-Mississippi and see if you finish by three-Mississippi.

Wind speeds in Canada are given in meters per second and in the United States, in knots (nautical miles per hour). It is handy that the conversion from one to the other is close to "two;" double meters per second to get knots (approximately).