Question

A closed metallic cylindrical box is 1.25 m high and its base radius is 35 cm. If the metal sheet costs Rs. 80 per $m^2$, the cost of the material used in the box is........

• A. Rs. 281.60
• B. Rs. 290
• C. Rs. 340.50
• D. Rs. 500

Answer 1

Answer: (A)

Rs. 281.60

Given,
height of cylinder = h = 1.25 m = 125 cm,
radius of the base = r = 35 cm
As the qty of metal sheet used to make the cylinder = total surface area of the cylinder.
But total surface area of closed metalic cylinder = $2\ast \Pi \ast r\ast (r+h)$
Total surface area = 2 * (22/7) * 35 * (35 +125) = 44 * 5 * 160 = 35200 cm^2.
Therefore Total surface area = 35200 / (100*100) m2= 3.52 m^2
Given that cost of material = Rs. 80 / m^2.
Therefore total cost of material used = 80 * 3.52 = Rs. 281.60
Answer (A) Rs. 281.60