Question

The dyameter of a wheel of abus is 90cm which makes 315 revolution per minute diameter its speed in kilometre per hour

Answer 1

The question that you have asked is wrong , after some corrections ,I found that the real question is :

The diameter of a wheel of a bus is 90 cm long which makes 315 revolutions per minute . Determine its speed in kilometre per hour .

answer : 53.43 kilometre per hour

step by step explanation:

Given:

diameter of the wheel of the bus = 90 cm.

number of revolutions make by the wheel in 1 minute = 315

distance travelled in 1 revolution

= perimeter of the wheel

= πd

= (22/7) × 90 cm

= (22×90/7) cm

= 1980/7 cm

Then, the distance travelled in 315 revolutions

=(1980/7) cm × 315

= 89100 cm

speed of the bus = distance / time

= 89100 cm / 1 min

= 89100 cm per minute

For converting the speed of the bus into kilometre per hour , we have to divide 89100 cm by 100000 because 1 centimetre = 1 / 100000 km and we have to divide 1 minute by 60 because 1 minute equals 1 / 60 hours.

So, 89100 cm / 1 min

= (89100 cm / 100000) /( 1 min/60)

= 0.891 km / (1 /60) h

= (0.891 / 1 /60) km / h

= 0.891 × 60/ 1 h

= 53.43 km / 1 h

= 53.43 kilometre per hour