Question

A car covers first half of the total distance with speed of 36km/hr and the second half with speed of 5km/hr .find the average speed of the car

Answer 1

Answer:

car cover first half of the total distance with speed 36 km/h and second half with speed of 54 km/h per hour.

To find : The average speed of the car?

Solution :

Let the distance covered in first half be x.

So second half distance will also be x.

We know, \text{Time}=\frac{\text{Distance}}{\text{Speed}}Time=

Speed

Distance

Time at first half is

t_1=\frac{x}{36}t

1

=

36

x

Time at second half is

t_2=\frac{x}{54}t

2

=

54

x

Average speed of the car is,

\text{Average Speed}=\frac{\text{Distance}}{\text{Tiime}}Average Speed=

Tiime

Distance

\text{Average Speed}=\frac{2x}{\frac{3x+2x}{108}}Average Speed=

108

3x+2x

2x

\text{Average Speed}=\frac{2x\times 108}{5x}Average Speed=

5x

2x×108

\text{Average Speed}=\frac{2\times 108}{5}Average Speed=

5

2×108

\text{Average Speed}=43.2Average Speed=43.2

Therefore, Their average speed is 43.2 km/hr.