Question

A truck driver drives $20km$ down the road in 5 minutes. He then reverses and drives $12km$ back down the road in 3 minutes. What is his average velocity?

• A. $4km/min$
• B. $2km/min$
• C. $3km/min$
• D. $60km/h$

Answer 1

The correct option is D. $60km/h$.

Given,
Total distance covered $=20km+12km=32km$
Displacement $=20-12=8km$
Time taken $=5+3=8$ minutes = $\frac{8}{60}h=\frac{2}{15}h$.

Average velocity = $\frac{Totaldisplacement}{Totaltimetaken}$

Average velocity $=\frac{8km}{\frac{8}{60}}=60km/h$.