Step-by-step explanation:
we paint the walls and ceilings.
and we ignore any doors or windows (no information about them).
so, each room has then 5 rectangles : 4 walls and 1 ceiling.
when we say a room is 14 ft × 10 ft, this also means there are 2 sides of 14 ft and 2 sides of 10 ft.
and the area is 14×10 ft².
the area of the ceiling is the same as the area of the floor : 14×10 = 140 ft²
for the walls we have 2 rectangles of 14×8 = 112 ft², and 2 rectangles of 10×8 = 80 ft² (remember, the height of the room is 8 ft).
for the sister's room it is similar.
just a 12×10 = 120 ft² ceiling.
and 2 rectangles of 12×8 = 96 ft² and again 2 rectangles of 10×8 = 80 ft² as walls.
altogether we have then
140 + 112 + 112 + 80 + 80 + 120 + 96 + 96 + 80 + 80 ft²
that is in total
996 ft²
how many gallons of paint do we need for this ?
well, 1 gallon per 250 ft².
so, how often does 250 fit into 996 ?
996 / 250 = 3.984 gallons.
since we get the paint most likely only in quantities of gallons, we need 4 gallons for the paint job.
