Question

A car travels along straight line for first half time with a speed of 40 km/h and the second half with a speed of 60km/h find the average speed of the car ??

Answer 1

Answer:

Average speed of car will be 48 km/hr  

Explanation:

Let the total distance is 2d

It is given that first half of the distance car travels with a speed of 40 km/hr

So time taken to cover half of the distance $t_1=\frac{d}{40}hr$

Second half of the distance is covered with a 60 km/hr

So time taken to cover second half of the distance $t_2=\frac{d}{60}hr$

So total time to cover 2d distance $t=\frac{d}{60}+\frac{d}{40}=\frac{5d}{120}$

Average speed is the ratio of total distance to total time

So average speed $=\frac{2d}{\frac{5d}{120}}=48km/hr$

So average speed of car will be 48 km/hr