Question

The diameter of the wheel of a car is 77 cm.How many revolutions will it make to travel 121 km?

Answer 1

Diameter of the wheel = 77 cm = 77 / 100000 Km = 0.00077 km.

So the circumference of the wheel = 2 x 22/7 x r = 22/7D = 22/7 x 0.00077 = 0.00242 Mts.

The distance travelled by the car = 121 Kms.

So the number of revolution the wheel will take to travel 121 Kms = 121 / Circumference of the wheel

= 121/0.00242 = 50000 nos.

Ans: 50000 Nos.

Answer 2

Pi *d is the circumference of the wheel considering it doesn't slip then distance covered = 'n' revolutions * circumference of the wheel
1,21,00,000 cm = n*pi*d=(22/7*77*n)
12100000/(11*11*2) = n
1,00,000/2 = 50,000 = n