1.

The diameter of a roller, 120 cm long, is 84 cm. If it takes 500 complete revolutions to level a playground, find the cost of levelling it at Rs 5 per square metre.

Answer» Radius of the roller, r = 42 cm, and its length, h = 120 cm
Area covered by the roller in 1 revolution
= curved surface area of the roller
`= (2pi rh)` sq units
`= (2 xx (22)/(7) xx 42 xx 120) cm^(2) = 31680 cm^(2)`
Area covered by the roller in 500 revolutions
`(31680 xx 500) cm^(2) = ((31680 xx 500)/(100 xx 100)) m^(2) = 1584 m^(2)`
`:.` area of the playground `= 1584 m^(2)`
Cost of levelling the playground `= Rs (1584 xx 5) = Rs 7920`


Discussion

No Comment Found

Related InterviewSolutions