The diameter of roller 1.5 m long is 84 cm. If it takes 100 revolution

1.	The diameter of roller 1.5 m long is 84 cm. If it takes 100 revolutions to level a playground, find the cost of levelling this ground at the rate of 50 paise per square meter.
Answer» Given, Diameter of roller = 84 cm So radius of roller =\(\cfrac{84}2\) = 42 cm = .42 m Length of roller = 1.5 m Area covered by roller in one revolution = 2πrh = 2 \(\times\cfrac{22}7\times \)4.2 \(\times\) 1.5 = 3.96 m² Area covered by it in 100 revolution = 100 × 3.96 = 396 m² Cost of levelling 1m² area = Rs. .50 ∴cost of levelling 396m² = .50 × 396 = Rs. 198

The diameter of roller 1.5 m long is 84 cm. If it takes 100 revolutions to level a playground, find the cost of levelling this ground at the rate of 50 paise per square meter.

Answer»

Given,

Diameter of roller = 84 cm

So radius of roller =\(\cfrac{84}2\) = 42 cm = .42 m

Length of roller = 1.5 m

Area covered by roller in one revolution = 2πrh = 2 \(\times\cfrac{22}7\times \)4.2 \(\times\) 1.5 = 3.96 m²

Area covered by it in 100 revolution = 100 × 3.96 = 396 m²

Cost of levelling 1m² area = Rs. .50

∴cost of levelling 396m² = .50 × 396 = Rs. 198