MOVES Puzzle-Solving Meet-Up
Solution to Oskar’s Puzzle
- If the group has six participants, each participant splits their age randomly in six parts that add up to their age. For example, if your age is 55, then the following is possible split: 34, 20, -15, 60, -8, -36. As you can check: 34 + 20 – 15 + 60 – 8 – 36 = 55.
- Next, send five of the parts via private messaging to each of the five other participants and keep the remaining part for yourself.
- Similarly, you receive five parts privately from the other participants.
- Add your remaining part from step 2 and the five received parts from step 3. Then divide this sum by six.
- Share the result of step 4 with the group.
- Similarly, you receive five results from the other participants in the group.
- Add your result from step 4 to the five other results from step 6. Now you all know the average age of the group, while nobody has learned anything about people’s individual ages.