Question

39. A car moves for half of its time at 80 km/h and for
rest half of time at 40 km/h. Total distance covered
is 60 km. What is the average speed of the car?
A. 60 km/hr
B. 80 km/hr
C. 120 km/hr
D. 180 km/hr

Answer 1

Answer:

A) 60 km/hr

Let the time taken be 't' hours.

average speed= total distance covered/total time taken

distance covered with 80km/h speed.

80*t/2=d1

40t=d1

distance covered with 40 km/h speed

40* t /2=D2

20t=D2

average speed of car= (40t+ 20t)/t

60km/h is the average speed