Question

the diameter of a roller 120m long is 84cm.If it takes 500 complete revolutions to levwl a playgrpund,find the cost of levelling it at the rate of rupees 2per sq. metre.

Answer 1

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Diameter = 84cm$<b><font face=copper black size=4 color=purple>$

Radius = 42cm
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Height = 120cm
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1 revolution = LSA of roller
$<b><font face=copper black size=4 color=blue>$
= 2 x (22/7) x 42  6 x 120
$<b><font face=copper black size=4 color=red>$
= 31680 cm2
$<b><font face=copper black size=4 color=purple>$
So, 500 revolutions = 31680 x 500
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= 15840000cm2
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1 cm2 = .0001m2
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So,  15840000cm2 = 1584 m2   
$<b><font face=copper black size=4 color=black>$
Cost = 1584 x .30
$<b><font face=copper black size=4 color=orange>$
= Rs 475.20