+1911 In a row of five squares, each square is to be colored either red, yellow, or blue, so that no two consecutive squares have the same color. How many ways are there to color the five squares, if there must be at least three yellow squares?
+1199
In a row of five squares, each square is to be colored either red, yellow, or blue, so that no two consecutive squares have the same color. How many ways are there to color the five squares, if there must be at least three yellow squares?
In order to avoid having two yellows next to each other,
the three yellows must occupy squares 1, 3, and 5.
That leaves squares 2 and 4 to account for, and two
colors do it with. There are only four ways.
Red Red Blue Blue Red Blue Blue Red
So, the answer is four ways.
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