Question

A car travels at a speed of 40 km/h for 10 min then at 55 km/h for 20 min ang finally at 20 km/h for 20 minutes. What is the average speed of the car

Answer 1

u=20

v=55

t=10

v=u+at

55=10+a×10

55/10=+0+a

5.5-10=a

9.5=a

a=9.5

Answer 2

given

speed1= 40km/hr

time1= 10 min

= 600 seconds

speed2= 55km/hr

time2= 20 min

= 1200 sec

speed3 = 20 km/hr

time2= 20 min

= 1200 seconds

to find

average speed

solution

avg speed= speed1 +speed2 +speed3/3

40+55+20/3

115/3

38.3 km/hr

hope it helps