Question

4) 0.25m2 to mm2
1m=1000mm
1m2=1000*1000mm2
=10^6mm2
Therefore 0.25m2= 0.25*10^6mm2
= 25/100 *10^6
25*10^4
=2.5*10^5mm2
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Answer 1

It is given that length, breadth and height of a room are 8 m, 5 m and 3 m respectively.

Area of four walls of the room is: 2h(l+b)

A=2h(l+b)=2×3(8+5)=6×13=78 m2

Area of the ceiling is: 

A=l×b=8×5=40 m2

Total area of the four walls and the ceiling of the room is 78+40=118 m2

It is given that cost of white washing is Rs.15/m2, therefore,

Total cost of white washing is:

118×15=1770

Hence, the cost of white washing the walls is Rs.1770.