A classroom is 7 m long, 6 m broad and 3.5 m high. Doors and windows o

1.	A classroom is 7 m long, 6 m broad and 3.5 m high. Doors and windows occupy an area of 17 m2. What is the cost of white washing the walls at the rate of Rs. 1.50 per m2.
Answer» Given, Dimensions of class room = 7 m × 6 m ×3.5 m Where, Length = 7 m, Breadth = 6 m , Height = 3.5 m Area of four walls (including doors & windows) = 2(l x h + b x h) = 2(7 x 3.5 + 6 x 3.5) = 91 m² Then, Area of walls without doors & windows = area including doors & windows – area occupied by doors & windows Area of only walls = 91 – 17 = 74 m² So, Cost of white washing 1 m² area of walls = Rs.1.50 ∴ Total cost of white washing = 74 × 1.50 = Rs.111

A classroom is 7 m long, 6 m broad and 3.5 m high. Doors and windows occupy an area of 17 m2. What is the cost of white washing the walls at the rate of Rs. 1.50 per m2.

Answer»

Given,

Dimensions of class room = 7 m × 6 m ×3.5 m

Where,

Length = 7 m, Breadth = 6 m , Height = 3.5 m

Area of four walls (including doors & windows) = 2(l x h + b x h)

= 2(7 x 3.5 + 6 x 3.5) = 91 m²

Then,

Area of walls without doors & windows = area including doors & windows – area occupied by doors & windows

Area of only walls = 91 – 17 = 74 m²

So,

Cost of white washing 1 m² area of walls = Rs.1.50

∴ Total cost of white washing = 74 × 1.50 = Rs.111