Question

A storage tank consist a circular cylinder with a hemisphere adjoined on their ends the external diameter of the cylinder is 1.4m and length is 8m. Find the cost of painting it on the outside at the rate of Rs. 10 per m2.

Answer 1

Answer:

ANSWER

We have,

r=0.7m, h=8m

∴ Total surface area = 2πr

2

+2πrh=2πr(r+h)=2×

7

22

×0.7×8.7m

2

Required cost = Rs. {2×

7

22

×0.7×8.7×10}=Rs.382.80

Answer 2

Given:-

• The external diameter of the cylinder is 1.4m and length is 8m.
• The rate of Rs. 10 per m².

To find:-

• Find the cost of painting...?

Solutions:-

• The external diameter of the cylinder is 1.4m
• The external Radius of the cylinder is 1.4m/2 = 0.7m
• Height of the cylinder = 8m

Now,

The total surface area of the storage tank.

Total surface area = Surface area of cylinder + Surface area of the hemisphere.

Surface area => 2πrh + 2πr²

=> 2 × 22/7 × 0.7 × 8 + 2 × 22/7 × (0.7)²

=> 44 × 0.1 × 8 + 44/7 × 0.7 × 0.7

=> 44 × 0.1 × 8 + 44 × 0.1 × 0.7

=> 35.2 + 3.08

=> 38.28m²

Therefore,

The external surface area of the storage tank is 38.28m².

Now,

The rate of the storage tank on outside = Rs. 10 per m².

So,

The cost of painting the storage tank on outside

=> 38.28 × 10

=> 38280

Hence, the cost of painting the storage tank on outside is Rs. 382.80.