Answer:
Lyana will need 4 cans of paint to paint her whole room or only 3 if she doesn't paint the floor.
Step-by-step explanation:
Firstly we need to know how much paint she will need to use.
The area of her room is given by 2(ac+bc), where a is the length, b is the width and c is the height.
Applying that we get that the area of her room is 2*12*18+2*18*8=720.
This applies if we assume that she also paints the floor. If she doesn't we need to subtract the area of the floor which is 12*18=216. So 720-216=504
She will paint her room twice she the amount of paint she needs is twice the area:
720*2=1440
or if she does not paint the floor
504*2=1008
Now we answer how many cans is that by dividing by 400 and rounding up.
1440/400=3.6 she needs, therefore, 4 cans
1008/400=2.52 she needs 3 cans
