The diameter of each wheel of car is 70 cm. If each wheel rotates 400 times per minutes, then the speed of the car (in km/hr) if : $$\left( {{\text{Take }}\pi = \frac{{22}}{7}} \right)$$

A. 5.28 km/hr

B. 528 km/hr

C. 52.8 km/hr

D. 0.528 km/hr

Answer: Option C

Solution(By Examveda Team)

Circumference of wheel = 2πr
⇒ 2πr
⇒ 2 × $$\frac{22}{7}$$ × $$\frac{70}{2}$$
⇒ 220 cm
Speed per hours :
= $$\frac{{220 \times 400 \times 60}}{{1000 \times 100}}$$
= 52.8 km/hr