Question

the diameter of a wheel of a car is 63cm how many revolutions will it make to travel 7.9km

Answer 1

radius= 31.5
circumference of wheel=2× 22/7×31.5
no.of revolution=2×22/7×31.5÷7.9

Answer 2

Given :

the diameter of a wheel of a car is 63cm

To Find :

how many revolutions will it make to travel 7.9km

Solution:

Diameter of wheel = 63 cm

Radius of wheel =$\frac{63}{2}=31.5 cm$

Circumference of wheel = $2 \pi r = 2 \times \frac{22}{7} \times 31.5=198 cm$

So, Distance covered in 1 revolution = 198 cm

1 km = 100000 cm

198 cm =$\frac{198}{100000}=0.00198 km$

So, No. of revolutions in covering 0.00198 km = 1

No. of revolutions in covering 1 km =$\frac{1}{0.00198}$

No.of revolutions in covering 7.9 km = $\frac{1}{0.00198} \times 7.9=3989.89$

Hence it make 3990 revolutions to cover 7.9 km