A class room is 8m long, 7.5m wide, and 2.8m high. The wall and ceiling are to be painted.?

Question

a. how many square metersof area will be painted, allowing 16.8m2 for door and windows?

b. If a paint can be bought by the gallon and 1 gallon will cover about 52m2, how many gallons of paint must be bought if 2 coats of paint are desired?

help

Answer 1

the answer is 130 msq not 190msq,cos ur not gonna paint the floor and so u'll need 5 gallons exactly.
the caculation is pretty simple
construct a rough skettch of the dimensions
lenght of the2 rectangular walls =8m,
their height [now the breadth] = 2.8m,
total area of 2 walls = 2*8*2.8= 44.8msq

now the other 2 walls
lenght = 7.5m
breadth = 2.8m
total area of these walls = 2*7.5*2.8 = 42msq

now for ceiling and not the floor
lenght = 8m
breadth = 7.5m
area = 8 * 7.5 = 60msq

total area 2 b painted leaving windows is 60 +42+44.8 -16.8 =130msq

2 paint 2 coats double the area that is 260 msq
required paint is 260/52 = 5 gallons
right!!!

Answer 2

Area of walls = 2 (8 x 2.8) + 2 (7.5 x 2.8) m²
Area of walls = 44.8 + 42 m²
Area of walls = 86 . 8 m²
Area of doors and windows = 16.8 m ²
Net area of walls = 70 m ²
Area of floor = 8 x 7.5 m ² = 60 m ²
Area to be painted = 130 m ²
2 coats are used = 260 m ²

52 m ² <------> 1 gallon
260 m ² <-----> 260 / 52 gallons = 5 gallons

Answer 3

Hi,

Total suface area = 2(7.5 x 2.8 + 7.5 x 8 + 2.8 x 8) = 206.8 m²

206.8 m² - 16.8 m² for door & windows = 190 m²

190 m² is the total surface area to be painted <== answer


With 2 coats of paint, plan on 2 x 190 m or 380 m² to be painted

Since 1 gallon covers 52 m², then 380/52 = 7.307 gallons

Since they don't sell .307 gallons, 8 gallons will be needed

8 gallons of paint are needed. <== answer

I hope that helps!! :-)

Answers were 190 m² and 8 gallons

Answer 4

a. 2 * 8 * 2.8 + 2 * 7.5 * 2.8 + 7.5 * 8 -16.8 = 130 m^2

b. 130 * 2/52 = 5