Question

A room measures 6 m by 5 m by 4 m. Find the paint required in litres, to paint the walls with 2 coats of paint if a litre of paint is used to cover 18 m² in 1 coat. The windows and doors occupy 10% of the wall area.

Answer 1

We know that,

The curved surface area of a cuboid is 2l + b × h,

Then, area of the walls is 26 + 5 × 4 = 88 m²

Now, given that the windows and doors occupy 10% of the wall area,

Then, area occupy by windows and doors is 10% of 88 m²

= `10/100 xx 88`

= 8.8 m²

Now area to be paint = Area of the walls – Area occupy by windows and doors

= 88 – 8.8

= 79.2 m²

Paint the walls with 2 coats of paint = 79.2 × 2 = 158.4 m²

Now, 18 m² can be painted in 1 litre

1 m² can be painted in `1/18` litre

Then, 158.4 m² can be painted in `1/18 xx 158.4` = 8.8 litres

Therefore, the pain required is 8.8 litres.