The wheels of a car make 2500 revolutions in covering a distance of 4.95 km.

Distance $=4.95 \mathrm{~km}=4.95 \times 1000 \times 100 \mathrm{~cm}$

$\therefore$ Distance covered by the wheel in 1 revolution $=\frac{\text { Total distance covered }}{\text { Number of revolutions }}$

$=\frac{4.95 \times 1000 \times 100}{2500}$

$=198 \mathrm{~cm}$

Now,
Circumference of the wheel = 198 cm

$\Rightarrow 2 \pi r=198$

$\Rightarrow 2 \times \frac{22}{7} \times r=198$

$\Rightarrow r=\frac{198 \times 7}{44}$

$\Rightarrow r=31.5 \mathrm{~cm}$

$\therefore$ Diameter of the wheel $=2 r$

$=2(31.5)$

$=63 \mathrm{~cm}$