Question

A roller 140 cm long has a radius of 35 cm. To level the playground,it takes 980 complete revolutions. Determine the cost of levelling the playground at rate of 75paise/square metre​

Answer 1

Answer:

Step-by-step explanation:

For the roller,

height, h = 140 cm = 1.4  m

radius, r = 35 cm = 0.35 m

The roller takes 980 revolutions to level the playground. 

Thus, Area covered by roller = Area of playground.

∴Area of playground = 980 * Curved Surface Area of Roller

                                  = 980 * 2πrh

                                  = 980 * 2 * 22/7 * 0.35 * 1.4

                                  = 21128.8 / 7 

                                  = 3018.4 m²

Thus, area of the playground is 3018.4 m²

Area                         Cost

1m²                          75 paise = Rs 0.75

3018.4 m²                   (?)

= 3018.4 * 0.75

= Rs. 2263.8

Thus, the cost of levelling the playground should be Rs 2263.8

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