Question

The diameter of a road roller is 90 cm and is 2m 10 cm in length. If it takes 400 revolutions to level a playground, find the cost of leveling the ground at Rs 2.25 per square meter

Answer 1

The cost of leveling the ground is Rs 5340.6

Explanation:

Given:

Diameter of the road roller = 90 cm

Length of the road roller = 2m 10 cm

Total number of number of revolution = 400

Cost of leveling = Rs 2.25 per square meter

To Find:

Total cost of leveling the ground = ?

Solution:

Step 1 : Finding the surface area of the road roller

Converting cm to m

90 cm = 0.9 m

2m 10 cm = 2 + 0.1 m = 2.1 m

Surface area of the road roller = surface are of the cylinder

=
`2\pi r h`

r= radius of the road roller

r=
`(0.9)/(2)`

r=0.45

Now surface area is

=>
`2 * \pi * 0.45 *`

=>
`6.28 * 0.45 * 2.1`

=>
`2.826 * 2.1`

=>5.934

Step 2 : Finding the area of the ground

Total area of the ground = Surface area of the road roller X number of revolutions

=>
`5.934 * 400`

=> 2373.6

Step 3 : Finding the cost of leveling

Total cost of leveling = area of the ground X Cost per square meter

=>
`2373.6* 2.25`

=>5340.6