Question

A car moves through 20 km at a speed of 40 km/h, and next 40 km at a speed of 80 km/h. Calculate its average speed.

Answer 1

Explanation:

total distance covered by car=20+40=60

V1=40,S1=20

V1=S1/t1

t1=1/2hr

V2=80,S2=40

T1=1/2

total time =1hr

average speed=total distance/total time

=60km/hr

Answer 2

Answer:

given,

first speed=40km/h and distance=20km

so find the time=40/20=2

now second speed is80km/h and distance=40. so taken time=80/40=2

so total time=2+2=4

and given total distance=40+20=60

so average speed=total dist./total time

therefore average speed=60/4=15