Question

the the capacity of an open cylindrical tank is 2079 metre cube and the diameter of its base is 21 m find the cost of plastering its inner surface @ rupees 40 per square metre

Answer 1

Volume = 2079m3
2079=22/7*21/2*21/*h
H = 6m
CSA = 396m2
Cost = Rs. 15840
Hope it helps!!!

Answer 2

Answer:

The cost of plastering its inner surface is Rs. 33382.125.

Step-by-step explanation:

Given : The capacity of an open cylindrical tank is 2079 meter cube and the diameter of its base is 21 m.

To find : The cost of plastering its inner surface @ rupees 40 per square meter.

Solution :

Volume V=2079 meter cube.

Diameter = 21 m

Radius $r=\frac{21}{2}=10.5$

Volume of cylinder is  

$V=\pi r^2 h$

$2079=(3.14) (10.5)^2 h$

$2079=(3.14) (110.25) h$

$h=\frac{2079}{346.185}$

$h=6 m$

Area of inner surface is

$A=2\pi rh+\pi r^2$

$A=2(3.14)(10.5)(6)+(3.14) (10.5)^2$

$A=395.64+346.185$

$A=741.825 m^2$

Cost of plastering its inner surface is

$C=45\times 741.825=33382.125$

Therefore, The cost of plastering its inner surface is Rs. 33382.125.