Question

A car moves for half of its time at $80km/h$ and for rest of time at$40km/h$. Total distance covered is $60km.$ What is the average speed of the car

• A. $60km/h$
• B. $80km/h$
• C. $120km/h$
• D. $180km/h$

Answer 1

The correct option is A $60km/h$

Let total times bed=$thr$
so distance covered $1^{st}$ half=$80\times \frac{y}{2}$
=$40t$
distance covered in $2^{nd}$ half = $40\times \frac{t}{2}$
=$20t$
A.V. speed=$\frac{Totaldistance}{totaltime}$
=$\frac{40t+20t}{t}$
=$\frac{60t}{t}$
=$60km/h$