The diameter and length of a roller is 120 cm and 84 cm respectively. To level the graound, 200 rotations of the roller are required. Find the expenditure to level the ground at the rate of ₹ 10 per sq m.

Answer

₹ 6336.

Explanation

The diameter fo the roller = 120 cm
`:. " its radius ( r)"= 120/2=60 cm`
its length (h) `= 84 cm`
Curved surface area of the roller `= 2pirh`
`2xx22/7xx60xx84`
`=31680 cm^2`
`=31680/10000m^2 …(1m^2=10000cm^2)`
`=3.168 m^2`
Area of ground levelled in 1 rotation is `3.168 m^2`
`:.` Area of ground levelled in 200 rotations
`=200xx3.168= 633.6 m^2`
Cost of levelling the ground per `m^2=₹10`
`:.` Total cost of levelling the ground `= 633.6 xx10 ₹6336`