Question

OL
5. The length, breadth and depth of the inside of an open safety tank are 6m. 4 m and 7m
respectively. Find the cost of cementing the inside of the tank at the rate of ? 42 per
m” [Hint : Area of the top surface is to be excluded]​

Answer 1

Appropriate question:

• The length, breadth and depth of the inside of an open safety tank are 6m,4m and 7m respectively. Find the cost of cementing the inside of the tank at the rate of 42/m² [Hint : Area of the top surface is to be excluded]

Answer:

Given:

• Length of tank (l) = 6m
• Breadth of tank (b) = 4m
• Depth of tank = Height of tank (h) = 7m
• Rate of cementing = ₹42/m²

To Find:

• Cost of cementing of open tank

Solution:

Here, in the tank the top surface is open and that's why, cementing will be done in only four walls and base.

To find cost of cementing, first of all we need total area of tank.

Total Area of tank = Area of 4 walls + Area of base

→Total Area= CSA of cuboid + Area of rectangle

→Total Area = 2(l+b)h + l × b

→Total Area = 2(6+4)×7 + 6×4

→Total Area = 2×10×7 + 24

→Total Area = 140 + 24

→Total Area = 164

$\therefore$ Total Area of tank = 164m²

Finding cost of cementing:

Now,

∵ Cost of cementing 1m² = ₹42 •••••(Given)

$\therefore$Cost of cementing 164m² = 164×42 = ₹6888

Hence,

• Cost of cementing inside the tank is ₹6888

Answer 2

Answer:

The cost of cementing inside the tank is $6888.

Step-by-step explanation:

Given :

• Length, breadth and depth (height) of the inside open safety tank are 6 m, 4 m and 7 m.
• Rate of cementing is $42 per sq metre.

To find :

• The cost of cementing inside the tank.

Solution :

[The shape of tank is cuboidal because it have length, breadth and height (or depth)]

• We have to find cost of cementing inside the tank so, for this first we need surface area of inside of the open tank.

• Surface area of inside of the open tank = 2(lb + bh + lh) - lb

[Where, l is length, b is breadth and h is height or depth]

Put all values :

$\implies$ Surface area = 2 × [(6 × 4) + (4 × 7) + (7 × 6)] - (6 × 4)

$\implies$ Surface area = 2 × (24 + 28 + 42) - 24

$\implies$ Surface area = (48 + 56 + 84) - 24

$\implies$ Surface area = 188 - 24

$\implies$ Surface area = 164

Thus,

Surface area of inside of the open tank is 164 m².

=> Cost of cementing 1 m² = $42

=> Cost of cementing 164 m² :

$\implies$ 164 × 42

$\implies$ 6888

Therefore,

The cost of cementing inside the tank is $6888.