The wheel of an engine of 300 cm in circumference makes 10 revolutions in 6 seconds. What is the speed of the wheel (in km/h)?

Explanation:-

Circumference = One revolution
Distance covered in 10 revolutions = 300 * 10 = 3000 cm = 30 m
30 meters are covered in 6 seconds.
Speed of the wheel = ³⁰/₆ = 5 m/s
5 m/s = ^(5*18)/₅ = 18 km/h. [To convert m/s to km/h, we use to multiply by factor ¹⁸/₅]