Question

A car is moving on a straight road covers one third of the distance with 20km/hr and the rest with 60km/hr. The average speed is ?

Answer 1

Let the total distance be 300m
It covered 100 m at 20km/h = 20×5/18 = 50/9 m/s
t = s/v
= 100÷50/9
= 100×9/50
= 18 seconds
It covered 200 m at 60 km/h = 60×5/18 = 50/3 m/s
t = s/v
= 200÷50/3
= 200×3/50
= 12 seconds
Average velocity = Total Distance/Total Time
= (100+200)/(18+12)
= 300/30
= 10 m/s
= 10×18/5
= 36 km/h

Hope it helps you ☺
Please mark as Brainliest ☺

Answer 2

Let the total distance be 3x
time taken to cover 1/3 of the distance= X/20

time taken to cover 2/3 of the distance= 2x/60= X/30
total time taken = X/20+X/30= 5x/60= X/12

Average speed = total distance/ total time
=( 3x)/ (x/12)

Average speed= 36 km / hr