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 $m^2$, then find the cost of the material used in the box.

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

Answer 1

The correct option is A Rs. $281.60$

Given height of cylinder $=h=1.25m=125cm$

Radius of the base $=r=35cm$

As the quantity of metal sheet used to make the cylinder $=$ total surface area of cylinder.

But total surface area of closed cylinder $=2\times \pi \times r\times (r+h)$

Total surface area $=2\times \frac{22}{7}\times 35\times (35+125)$

Total surface area$=44\times 5\times 160=35200c{m}^2$

$\therefore$ The total surface $=\frac{35200}{100\times 100}=3.52m^2$

Given that the cost of material $=Rs.80/m^2$

$\therefore$ The total cost of material used $=80\times 3.52=Rs.281.60$