a cross-country runner runs 10 km in 40 minutes. what is his average speed?

Answer:

7.5 km/h

Explanation:

Step1: Convert time to hours

$40\ \text{minutes} = \frac{40}{60} = \frac{2}{3}\ \text{hours}$

Step2: Calculate average speed

$\text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}} = \frac{10}{\frac{2}{3}} = 10 \times \frac{3}{2} = 7.5\ \text{km/h}$