Question

Saina Nehwal, a great Indian woman badminton player devotes two to three hours to a workout every morning in order to build her stamina and agility. As per a report in the newspaper, she runs on a treadmill for ten minutes with a speed of 6 km/hour and after a break of 5 minutes again for ten minutes with a speed of 12 km/hour. What is her average speed during workouts on the treadmill if she covered a total of 3km distance?

Answer 1

Step 1: Given data:

1. The speed of Saina is 6km/hour for 10 minutes.
2. After the break of 5 minutes, the speed of Saina is 12 km/hour for 10 minutes.

Step 2: Finding the average speed:

$\mathrm{Average}\mathrm{speed}=\frac{\mathrm{Total}\mathrm{distance}\mathrm{covered}}{\mathrm{Total}\mathrm{time}\mathrm{taken}}$

Total distance covered = 3 km

Total time taken = 10+5+10 = 25 min=$\frac{25}{60}hr$

$$\begin{gathered} \mathrm{Average}\mathrm{speed}=\frac{3}{{\displaystyle \raisebox{1ex}{$25$}\!\left/ \!\raisebox{-1ex}{$60$}\right.}} \\ =7.3km/hr \end{gathered}$$

Hence, Saina's average speed is 7.3 km/hr.