The wheel of a car has an outer radius of 28 cm. Calculate how far the car travels after one complete turn of the wheel, and how many times the wheel turns during a journey of 1 km.

Given, radius = 28cm

$$\text{Circumference} = 2\pi r = 2 \times \frac{22}{7} \times 28$$

$$= 176 \text{ cm} = 1.76 \text{ m}$$

Distance of journey: 1 km = 1000 m

$$\text{Revolutions} = \frac{1000}{1.76} = 568.18$$

$$\approx 568 \text{ revolutions (approx)}$$