Question

2. The length, breadth and height of a room are 5 m, 4 m and 3 m respectively. Find the
cost of white washing the walls of the room and the ceiling at the rate of ₹7.50 per m*
​

Answer 1

Given :-

Length = 5 m

Breadth = 4 m

Height = 3 m

To Find :-

Total cost

Solution :-

we know that

TSA = 2(lb + bh + lh) - lb

TSA = 2(5 × 4 + 4 × 3 + 5 × 3) - 5 × 4

TSA = 2(20 + 12 + 15) - 20

TSA = 2(47) - 20

TSA = 94 - 20

TSA = 74 m

Now

Total cost = 7.50(74)

Total cost = 555 rs

Answer 2

Gɪᴠᴇɴ :

• Length of a room = 5m

• Breadth of a room = 4m

• height of a room = 3m

Tᴏ Fɪɴᴅ :

• the cost of white washing the walls of the room

Cᴀʟᴄᴜʟᴀᴛɪᴏɴ :

Area of four wall = 2 ( l + b ) h

= 2 ( 5 m + 4 m ) 3 m

= 2 × 9 m × 3 m

= 54 sq.m

Area of floor = L × B

= 5 m× 4 m

= 20 sq.m

Total area = ( 54 + 20 ) sq.m

= 74 sq.m

now,

Cost of white washing = ₹( 74 × 7.50)

= ₹ 555

Hence, the cost of white washing

= ₹ 555