Question

A well 14 metre deep is 2 metre in radius find the cost of cementing the inner curved surface at the rate of rupees 2 per square metre

Answer 1

Answer:

The cost of cementing is Rs. 352.

Step-by-step explanation:

Given :

Depth of the well = 14 m

Radius = 2 m

Rate of cementing = Rs. 2 per m²

To find :

The Cost of cementing

Solution :

The cementing is to be done on the inner curve, so, the Curved surface area of the cylinder is required.

• Radius = 2 m
• Height = 14 m

★ CSA of cylinder = 2πrh

⇒ 2 × 22/7 × 2 × 14

⇒ 44 × 2 × 2

⇒ 44 × 4

⇒ 176 m²

Curved surface area = 176 m²

_________________________________

★ Cost of cementing,

To get the cost of cementing, multiply the rate of cementing by the CSA

⇒ 176 × 2

⇒ 352

Cost = Rs. 352

Therefore, the cost of cementing is Rs. 352.

Answer 2

Answer:

$\large{\underline{\boxed{\mathfrak\green{Cost \: of \: cementing = Rs.351.68 }}}}$

Given:-

• Depth of well(h) = 14 m
• Radius of well(r) = 2 m
• Rate of cementing = Rs.2 per m²

To find:-

• Cost of cementing = ?

Solution:-

As the inner curved surface is going to be cemented,so we have to find the area of inner curved surface.

As a well is like a cylinder,so we can find CSA of well using the formula of CSA of cylinder.

Now,

$\star\: \: {\boxed{\mathfrak\blue{Curved \: surface \: area = 2 \pi rh }}}$

• Putting values:-

⇒ CSA of well = 2 × 3.14 × 2 × 14

⇒ CSA of well = 175.84

$\rule{100}{2}$

Rate of cementing = Rs.2 per m²

We know,

$\star\: \: {\boxed{\mathfrak\pink{Rate \: of \: cementing = Required \: area \times Rate}}}$

• Putting values:-

➜ Cost of cementing = 175.84 × 2

➜ Cost of cementing = Rs.351.68

$\therefore{\underline{\rm{Cost \: of \: cementing = Rs.351.68 }}}$