Question

The radii of the front and the rear wheels of a race car are in the ratio 2 : 3. Find the ratio of the number of rotations they complete to cover 15
km.

Answer 1

Answer:

Given diameter of front wheels(2r)=80cm⇒r=40cm

diameter of rear wheels(2r)=2m⇒r=1m=100cm

In one revolution area covered is =2πr

∴ Distance covered by front wheel in 1400 revolutions =1400×2π(40)

Let us assume that to cover same distance rear wheel will take x revolutions=x×2π(100)

As both wheel will cover same distance ∴1400×2π(40)=x×2π(100)

x=

100

1400×40

=560

That means rear wheel will make 560 revolutions to cover the required distance.