Question

A car travels first half distance between two places with a speed of 40 km/hr and rest of the half distance with a speed of 60 km/hr. The average speed of the car is:

Answer 1

Answer:

Average speed of the car = 48 km/h

Step by step explanations :

Given that,

A car travels first half distance between two places

with a speed of 40 km/hr

and rest of the half distance with a speed of 60 km/hr.

1st Method :

let the total distance travelled by car

be s

so,

time taken to cover s/2 at 40 km/h

= (s/2)/40

= s/80 h

time taken to cover s/2 at 60 km/h

= (s/2)/60

= s/120 h

now,

Average speed of the car = total distance covered/total time taken

total distance covered = s

total time taken = s/80 + s/120

(3s + 2s) /240

5s/240

= s/48 h

so,

now we have,

distance covered = s

time taken = s/48

so,

Average speed = s/(s/48)

= 48s/s

= 48 km/h

so,

Average speed of the bus

= 48 km/h

________________

2nd Method :

let the 1st speed be V1

2nd speed be V2

so,

V1 = 40 km/h

V2 = 60 km/h

Average speed

= 2V1V2/(V1 + V2)

putting the values,

2 × 40 × 60/(40 + 60)

80 × 60/100

48 km/h

so,

Average speed of car = 48 km/h

Answer 2

Answer:48km/hr

Explanation:

Cover half of the distance with

60km /hr

And half with 40km/hr

Average speed=2v1 *v2/v1+v2

=2 (60)*(40)/60+40

=4800/100

=48km/hr