Question

a The diameter of a roller 150 cm long, is 98 cm. If it takes 300 complete revolutions to level a playground, find the cost of leveling it at 50 paisa per square meter is.​

Answer 1

=Rs475.20

Step-by-step explanation:

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 

           =2×722×42×120cm2=31680cm2

so, area covered by the roller is 500 revolution = (31680×500)cm2

                    =100×10031680×500m2=1584m2

hence , cost of levelling the playground = 1584×10030=Rs475.20