On Tuesday shanice bought five hats. On Wednesday half of all the hats that she had were destroyed. On Thursday there were only 17 left. How many did she have on Monday?

1 Answer



Let's work this problem backwards.

On Thursday, there are 17 hats:


On Wednesday, half the hats were destroyed, so what she had starting on Wednesday is half of what she had at the end of Wednesday (i.e. Thursday). This gives:


On Tuesday, we bought 7 hats. This means that on Wednesday we had 7 more hats than we did on Monday, which gives:


And so there were 27 hats on Monday.