- Mon Dec 18, 2017 5:52 pm
Thanks for the question. I'm not entirely sure of your question here, so I'm guessing you are wondering why the distribution isn't 3-3-3, perhaps? That distribution does exist, but that would be for total birthstones (3) in each ring (of which there are 3), hence the 3-3-3.
That 3-3-3 is fixed, and thus it is of minimal interest to us. However, it does tell us that there are 9 total birthstones used, and since those 9 stones come from 5 different types of birthstones, it helps lead us to the "9 into 5" distribution you see in the answer key. That distribution is far more varied, and thus of significantly more interest here.
From there, we see that there are 5 separate numbers in each distribution, and thus each number represents the usage of a separate birthstone type. each distribution also adds up to 9, which is the summation of all 9 stones that will be used across the 3 rings.
A tricky one, but an excellent example of how they can "hide" very complex distributions inside of what appear to be simple setups.
Please let me know if that helps. Thanks!