CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon


Question

A car travels from A  and B at a speed of $$20km/hr$$ and returns at a speed of $$30km/hr$$. The average speed of the car for the whole journey is


A
25km/hr
loader
B
24km/hr
loader
C
50km/hr
loader
D
5km/hr
loader

Solution

The correct option is B $$24km/hr$$
Lets consider $$X=$$ distance between A and B.
A car travels from A to B with speed of $$20km/h$$  at time,
$$t_1=\dfrac{x}{20}hr$$
A car return from B to A with speed $$30km/h$$ at time $$t_2$$
$$t_2=\dfrac{x}{30}hr$$
Average speed, $$v_{avg}=\dfrac{Total \,   distance}{Total \,   time}$$
$$v_{avg}=\dfrac{2x}{t_1+t_2}=\dfrac{2x}{\dfrac{x}{20}+\dfrac{x}{30}}$$
$$v_{avg}=\dfrac{2x}{x/12}$$
$$v_{avg}=2\times 12$$
$$v_{avg}=24km/h$$
The correct option is B.

Physics

Suggest Corrections
thumbs-up
 
0


similar_icon
Similar questions
View More


similar_icon
People also searched for
View More



footer-image