A person preparing for Olympic Games ran 9 km in 1 hour and 20 minutes, and then 12 km in 1 hour and 40 minutes. What is the average speed in km/hr?
A person preparing for Olympic Games ran 9 km in 1 hour and 20 minutes, and then 12 km in 1 hour and 40 minutes. What is the average speed in km/hr?
Explanation
7 km/hr is the correct answer.
Time =80min+100min=3hr Distance=9km+12km=21km Distance/time=21km/3hr=7km/hr