A car's wheel has a diameter of 70 cm. How many revolutions does each wheel make per minute when the car moves at 66 km/h? Take $\pi = \frac{22}{7}$.

Explanation

1. 01

   One revolution = circumference = $\frac{22}{7} \times 70 = 220$ cm.

2. 02

   66 km/$h = 66{,}00{,}000$ cm per hour = 1,10,000 cm per minute.

3. 03

   Revolutions per minute = $1{,}10{,}000 \div 220 = 500$.