The diameter of the driving wheel of a bus is 140cm. How many revolutions per minute must the wheel make in order to keep a speed of 66km per hour?

Explanation

To solve the problem, we need to find the number of revolutions per minute that the driving wheel of a bus must make to maintain a speed of 66 km/h, given that the diameter of the wheel is 140 cm.

### Step-by-Step Solution:

**Step 1: Calculate the Circumference of the Wheel**
The formula for the circumference \( C \) of a circle is given by:
\[
C = \pi \times d
...