Question

It costs Rs.$2200$ to paint the inner curved surface of a cylindrical vessel $10m$ deep. If the cost of painting is at the rate of Rs.$20$ per $m^2$. Find radius of the base.

• A. $1.75m$
• B. $2.75m$
• C. $1.25m$
• D. $3.75m$

Answer 1

Answer: (A)

$1.75m$

Total cost of point$=2200Rs.$
cost of point$/m^2=20Rs.$
depth of cylindrical vessel$=10m$
Inner curved surface area painted$=\frac{totalcost}{cost/m^2}=\frac{2200}{20}=110m^2$
Now, $2\pi rh=110m^{2}2\times \frac{22}{7}\times r\times 10=110r=\frac{110\times 7}{2\times 22\times 10}=1.75m$
$\therefore$ radius of the base is $1.75m$.