Question

The Diamond of wheel a bus is 90cm which makes 315 Revolution per minute determine its speed in kilometre per hour​

Answer 1

Diameter = 90 cm

It makes 315 revolution per min

As circumference = 2 pie r = pie × diameter

= 90 pie cm

So Distance covered per minute = 90 pie cm × 315

So Speed = 90 pie × 315 cm/min

= 90 pie × 315× 10^-5/ 1/60

= 60× 90×315× pie × 10^-5

= 5400 × 22/7 ×10^-5 × 315

= 16970.8 × 10^-5 × 315

= 53.235 km/h

Answer 2

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

$\huge\bold{Answer}$

We are given the diameter of the wheel of the bus.

Diameter - $90\:cm$

So, radius - $\frac{90}{2}$

= $45$

Circumference of the circle is -$2\pi r$

Putting the values, using $\pi$as $\frac{22}{7}$

=$2\times \frac{22}{2}\times 45$

Converting 45 cm in kilometers

= $2\times \frac{22}{2}\times \frac{45}{100000}$

We are given that the revolutions per minute - 315

So ,

= $2\times \frac{22}{2}\times \frac{45}{100000}\times 315$

Now, We are the given the value in per minute,

So,

= $2\times \frac{22}{2}\times \frac{45}{100000}\times 315\times 60$

=$\frac{37422000}{700000}$

= $53.46\:km/hr$

$\boxed{\textbf{Speed = 53.46 km/hr}}$