need help
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, and at lest three of the squares are red. How many ways are there to color the five squares?
We have R _ R _ R
For each of the blank spaces, there are 2 choices, so there are \(2 \times 2 = \color{brown}\boxed{4}\) cases.