Question

The cost of painting the inner curved surface area of a cylindrical container of depth 20 m is Rs. 8800. If painter takes Rs. 40 per metre square to paint the cylindrical container, then find radius of the cylindrical vessel.

• A. 1.75 m
• B. 3.5 m
• C. 7 m
• D. 6 m

Answer 1

The correct option is A

1.75 m

The cost of painting the inner curved surface = Rs. 8800.
Cost of painting per square meter = Rs. 40
Hence, area that was painted = 220 $m^2$
Thus inner curved surface area = 220 $m^2$
Inner curved surface area of cylinder = 2 $\pi$rh
Height of cylinder = 20 m
$\Rightarrow$ 2 πr(20) = 220
$\Rightarrow$ r =$\frac{220\times 7}{20\times 2\times 22}$
$\Rightarrow$ r = 1.75 m
Hence, radius of the cylinder = 1.75 m