Question

A boy in a car realises that he crosses 21 trees in 60 seconds. If each pair of trees is 50 m apart, what is the speed of the car in km/h?

Answer 1

HEY DEAR ...

Here the first tree is crossed when the car just started because the the first tree is parallel to the car .

So when the car passes 2 tress the distance covered is 50 metre. And from the next trees the distance will be 50 metre for each tree.

So the distance covered is 20*50 = 1000metre.

i.e- 1km

Time taken is 60 second = 1 minute

So an hour has 60 minutes

If 1.0km in 1 minute then

1.0*60 in 1 hour

So answer is 60km/ph

HOPE , IT HELPS ...