Answer:
10
Explanation:
So first it wants you to solve working backwards. This basically means to add up what you used and spilled, opposite of subtracting or using it. I will show that below.
a - You have 1.5 cans left. You painted 4 rooms, each needing 2 cans, making it 8 cans. Now you bought 9.5 cans. Then .5 of a can got spilled. So you bought 10 cans of paint.
Next is solving the equation. I'll explain below.
b - So simplify the equation, which will get x = 2.5. x represents the amount of paint used to paint each room. To represent the 4 rooms, multiply both sides by 4.
4x = 10. So, both b and a have the same answer, 10.