Question

A factory manufactures 120,000 pencils daily . The pencil are cylindrical in shape each of length 25 cm and circumference of base as 1.5 cm . Determine the cost of colouring the curved surfaces of the pencils manufactured in one day at ₹0.05 per dm².

Answer 1

Length of the pencil, h = 25 cm
circumference of the base = 1.5 cm
Curved surface area of the pencil which needs to be painted will be
$$\begin{gathered} CSA=circumference\times height \\ =1.5\times 25c{m}^2 \\ =37.5c{m}^2 \end{gathered}$$
= 0.375 dm²
Pencils manufactured in one day = 120000
So, the total area to be painted will be $120000\times 0.375d{m}^2=45000d{m}^2$
Cost of painting this area will be $45000\times 0.05=Rs2250$