+1678 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?
+1246
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?
Squares 1, 3, and 5 have to be the yellow ones.
That leaves squares 2 and 4. They can be
red red
blue blue
red blue
blue red
for a total of four ways to color the squares to satisfy the conditions of the problem.
.
