The radius of the wheel of a vehicle is 35 cm. The wheel makes 10 revolutions in 6 seconds. The speed of the vehicle is:

13.2 km/hr

radius of the wheel of a vehicle = 35 cm

Distance in 1 revolution = 2Πr = 70Π cm

Distance in 10 revolutions = 700Π cm = 7Π m 

The wheel makes 10 revolutions in 6 seconds

Speed = 7Π/6 = 11/3 m/sec = 11/3 * 36/10 = 66/5

The correct answer is Option (2) → 13.2 km/hr