This Month’s Problem
Consider this list of numbers
1, 1, 1, 4, 4, 4, 7, 7, 7, 10, 10, 10
Pick any 3 numbers from the list and add them together.
Repeat the process with a new set of numbers from the original list.
What do you notice about the sums?
Solution
The sum is always a multiple of 3.
Can you increase the list by six numbers so that selecting three of them will always result in a sum that is a multiple of 3?