Question

The diameter of a roller, 120cm long is 84cm. It takes 500 complete revolutions to level a Playground. Find the cost of leveling it at

the rate of Rs 25 per sq metre.​

Answer 1

Step-by-step explanation:

the diameter of Roller is 84cm we know that radius is half of the diameter .

we get,

radius \: of \: roller = 42cmradiusofroller=42cm

the roller is 120 cm long that is

height\:of\:roller \:=120cmheightofroller=120cm

CURVED SURFACE AREA OF CYLINDRICAL ROLLER

=2πrh

=2×22/7×42×120

=2×22×6×120

=31680sq.cm .

ROLLER TAKES 500 complete revolutions to level the playground

which means that its curved surface area revolves 500 times to level playground.

so,AREA OF PLAYGROUND

=500×31680

=15840000sq.cm

=158400sqm

THE COST OF LEVELLING 158400sqm area at the rate of 75 paise per sq.m

=158400×75

=11880000paise

WE KNOW THAT,

1₹=100paise

THEREFORE,

11880000/100

=118800₹

FINAL ANSWER:

THEREFORE,

THE COST OF LEVELLING THE PLAYGROUND IS ₹1,18,800