Question

a car travels 20 km distance at a uniform speed of 60 km per hour and the next 20 km at a uniform speed of 40 km per hour find the average speed of the car

Answer 1

for 1 situation-
Distance =20km
Speed = 60 km/ hr
time=d/s
=20/60
=1/3 hr
for 2 situation
Distance = 20km
Speed= 40km/hr
time= 20/40
= 1/2 hr.

Average speed= total distance /time
total time =1/3+1/2
=5/6 hr
= 40*6/5= 48km/hr.
avg. speed= 48 km/hr.