Question

A room is 8.5 m long 6.5 m broad and 3.4 m high it has two doors each measuring 1.5 my by 1m and two windows each measuring 2m by 1m .find the cost of painting its four walls at rupees 160 per metre square

Answer 1

Given:

Given the room dimension is 8.5 m by 6.5 m by 3.4 m

There are 2 doors.

Each door is 1.5 m by 1 m.

There are 2 windows.

Each window is 2 m by 1 m.

To Find:

The cost of painting its 4 walls at Rs 160 per m²

Solution:

Find the area of the 4 walls including the doors:

Area of the 4 walls = 2(8.5 + 6.5) x 3.4

Area of the 4 walls = 102 m²

Find the area of the two doors:

1 door = 1.5 x 1

1 door = 1.5 m²

2 doors = 1.5 x 2

2 doors = 3 m²

Find the area of the two windows:

one window = 2 x 1

one window = 2 m²

two windows = 2 x 2

two windows = 4 m²

Find the area of the 4 walls without the doors:

Area = 102 - 3 - 4

Area = 95 m²

Find the cost:

1  m² = Rs 160

95  m² = 95  x 160

95  m² = Rs 15,200

Answer: The cost is Rs 15,200

Answer 2

Given:

A room is 8.5 m long 6.5 m broad and 3.4 m high it has two doors each measuring 1.5 m by 1 m and two windows each measuring 2 m by 1 m .

To Find:

Find the cost of painting its four walls at rupees 160 per metre².

Solution:

Room walls

Length of room = 8.5 m

Breadth of room = 6.5 m

Height of room = 3.4 m

We know the formula of surface area of four walls of room:

Surface area of four walls = 2 (Length + breadth)×Height

Surface area of four walls = 2 (8.5 + 6.5)×3.4 = 102 m²

Doors

Length of door = 1.5 m

Breadth of door = 1 m

Shape of door is in rectangle, we know the formula of area of rectangle:

Area of rectangle = Length × breadth

Means:

Area of each door = Length × breadth

Area of each door = 1.5 × 1 = 1.5 m²

So area of two doors will be:

Area of both door = 1.5 × 2 = 3.0 m²

Windows

Length of window = 2.0 m

Breadth of window  = 1 m

Shape of window  is in rectangle, we know the formula of area of rectangle:

Area of rectangle = Length × breadth

Means:

Area of each window  = Length × breadth

Area of each window  = 2.0 × 1 = 2.0 m²

So area of two window  will be:

Area of both window  = 2.0 × 2 = 4.0 m²

Now net area of wall will become:

Net area of wall=Area of four walls-Area of door -Area of window

Net area of wall = 102 - 3.0 - 4.0 = 95 m²

Cost of painting

Cost of painting will be:

Cost = Price rate× Area

Cost = 160× 95

Cost =  15200 Rs.

Means the cost of painting its four walls is 15200 Rupees.