All Chapter 5 Puzzles

Puzzle #038: The Baker's Dozen
Summary: A baker sells bread in dozens. If he has 13 loaves of bread, how many dozens does he have?
Solution: 1 dozen and 1 loaf. The trick is that a baker's dozen is 13, so 13 loaves is exactly one baker's dozen.

Puzzle #039: The Baker's Dilemma
Summary: A baker has 10 loaves of bread. He wants to sell them in groups of 3. How many groups can he make?
Solution: 3 groups. He can make 3 groups of 3 loaves, with 1 loaf left over.

Puzzle #040: The Baker's Delivery
Summary: A baker has 10 loaves of bread and needs to deliver them in bags of 3. How many bags does he need?
Solution: 4 bags. He will have 3 loaves in 3 bags, and 1 loaf in the last bag.

Puzzle #041: The Baker's Scales
Summary: You have 9 identical-looking balls, one of which is slightly heavier. Using a balance scale, how can you find the heavier ball in just two weighings?
Solution: Place 3 balls on each side of the scale. If they balance, the heavier ball is among the remaining 3. If one side is heavier, the heavier ball is among those 3. Take the 3 balls from the heavier side (or the remaining 3 if they balanced) and place 1 on each side of the scale. If they balance, the third ball is the heavier one. If one side is heavier, that's your ball.

Puzzle #042: The Baker's Boxes
Summary: You have three boxes labeled 'Apples', 'Oranges', and 'Apples & Oranges'. Each box is incorrectly labeled. You can pick one fruit from one box. Which box should you pick from to correctly label all boxes?
Solution: Pick from the box labeled 'Apples & Oranges'. Since all labels are wrong, this box must contain either only apples or only oranges. If you pick an apple, you know this box is 'Apples'. The box labeled 'Oranges' must then be 'Apples & Oranges' (as it can't be Oranges and it can't be Apples), leaving the box labeled 'Apples' to be 'Oranges'. The reverse logic applies if you pick an orange.