Q14 of 45 Page 11

The walls and ceiling of a room are to be plastered. The length, breadth and height of the room are 4.5 m, 3 m and 350 cm, respectively. Find the cost of plastering at the rate of Rs. 8 per square metre.

Given: Length of room = 4.5 m


Breadth of room = 3 m


Height of room = 350 cm


To find: the cost of plastering.


Formula Used:


Area = l × b +2 (l × h + b × h)


Explanation:


Length of room = 4.5 m


Breadth of wall = 3 m


Height of wall = 350 cm =


So,


Area of ceiling + area of walls = l × b + 2(l × h + b × h)


= 4.5×3 +2(4.5×3.5+3×3.5)


=13.5+2(15.75+10.5)


=13.5+52.5


=66 m2


Cost of plastering 1 m2 area = Rs.8


∴ Cost of plastering 66 m2 area = 66 ×8


=Rs.528


Note: As we don’t plaster the floor. That’s why we have taken “l× b” only once.


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