Question

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 m2.
​

Answer 1

Answer:

Step-by-step explanation:

to find the area of wall to white wash  we need to find the total surface area(TSA)

TSA of cuboid =  2 (Length x Breadth+breadth x height + Length x height)

=2[(5 x 4)+(4 x 3)+(3x5)]

=2[20+12+15]

=2x 47

=94m^2

so cost = 94 x 7.50

= Rs 705

Answer 2

Correct question:-

The length,breadth and height of a room are 5m,4m and 3m respectively. Find the cost of white washing the walls of the room and the ceiling at the rate of 7.50/m²

Given:-

→Length of the room=5m

→Breadth of the room=4m

→Height of the room=3m

→Cost of white washing the walls and

ceiling of the room per m²= ₹.7.50

To find:-

→Cost of white washing the walls of the room and the ceiling at the given price/m².

Solution:

The formulae,which we must know before solving this problem are:-

•L.S.A of cuboid(four walls)=2(l+b)h

•Area of rectangle(ceiling)=l×b

Hence:-

Total area of the room to be white washed:-

=>Area of four walls+Area of the ceiling

=>L.S.A(Lateral surface area)+(l×b)

=>2(l+b)h+(l×b)

=>2(5+4)3+(5×4)

=>2×9×3+20

=>54+20

=>74m²

Thus,we got area to be white washed as 74m².

Now,cost of white washing:-

=>74×7.50

=>₹555

Thus,cost of white washing walls and ceiling of the room is ₹555.