You have a cola to divide with two friends. It’s a large cola, which is 24 ounces, in a large paper cup. You find three other cups that hold 5, 11, and 13 ounces respectively. How can you pour the cola around so that you make three equal portions? (Neglect the ice.)
- Fill the 13 from the 24.
- Now 24 has eleven, 5 and 11 each have zero, and 13 has thirteen: 11, 0, 0, 13.
- Dump five from 13 into 5.
- Now it’s 11, 5, 0, 8.
- Dump eight from 13 into 11.
- Now it’s 11, 5, 8, 0.
- Dump five from 5 into 13.
- Now it’s 11, 0, 8, 5.
- Fill the 13 from the 24.
- Now it’s 3, 0, 8, 13.
- Dump five from 13 into 5.
- Now it’s 3, 5, 8, 8.
- Dump five from 5 into the 24.
- Now it’s 8, 0, 8, 8. Everybody now has 8 oz. of flat, warm cola.