Question

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 leveling it at Rs 6per square meter.

Answer 1

Answer:

Clearly the roller is a right circular cylinder of height h=120 cm

and radius of its base =r=42 cm

∴ area covered by the roller in one revolution = curved surface area of the roller

=2×

7

22

×42×120cm

2

=31680cm

2

so, area covered by the roller is 500 revolution = (31680×500)cm

2

=

100×100

31680×500

m

2

=1584m

2

hence , cost of levelling the playground = 1584×

100

30

=Rs475.20

Step-by-step explanation:

mark as brainleast