A factory manufactures 1,20,000 pencils daily. The pencils are cylindrical in shape, each of length $25 cm$ and circumference $1.5 cm .$ Determine the cost of colouring the curved surfaces of the pencils manufactured in one day at Rs. 0.05 per $dm 2$ .

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Rs.7812

Rs.5589

Rs.3250

Rs.2250

answer is D.

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Detailed Solution

Given that, 1,20,000 pencils are manufactured daily.
Length of pencil is 25cm, circumference is 1.5cm.
Curved surface area of cylinder

= 2 π r h

CSA of the pencil,

⇒ 2 π r × h ⇒ 1.5 × 25 ⇒ 37.5 cm 2

Now,

1 dm = 10 cm

So, CSA of pencil

= 0.375 dm 2

One day pencil area in dm square is,

⇒ 120000 × 0.375 ⇒ 45000

Cost of coloring is,

⇒ 0.05 × 45000 ⇒ R s .2250

Thus, the cost of the coloring the pencil is Rs.2250.
Therefore, option (4) is correct.

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