A fourth grade student checked several sets of triples of three consecutive whole numbers, such as 10, 11, 12, and 20, 21, 22, and concluded that in three consecutive whole numbers, one of the numbers is always divisible by 3. A contestant was shown three envelopes; one colored purple, one colored yellow, and one colored blue, and told that one of these envelopes had a $1,000 prize. Later the contestant learned that the blue envelope and the yellow envelope were empty, and she concluded that the purple envelope had the $1,000 prize