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

She started with x boxes.

Then she bought 7 more, so now she has x + 2.

Then half of the boxes were destroyed.

She now has (x + 7) / 2.

She has 22 boxes.

(x + 7) / 2 = 22

x + 7 = 44

x = 37

She started with 37 boxes.