Maria bought seven boxes. A week later half of all her boxes were destroyed in a fire. There are now

Maria bought seven boxes. A week later half of all her boxes were destroyed in a fire. There are now only 22 boxes left. With how many did she start?

Let the number of boxes Maria started with be b. We're given the following pieces:

• She starts with b
• She bought 7 boxes. So we add 7 to b: b + 7
• If half the boxes were destroyed, she's left with 1/2. So we divide (b + 7)/2
• Only 22 boxes left means we set (b + 7)/2 equal to 22

(b + 7)/2 = 22

Cross multiply:
b + 7 = 22 * 2
b + 7 = 44

Type this equation into our search engine to solve for b and we get:
b = 37