In his pocket, a boy has 3 red marbles, 4 blue marbles, and 4 green marbles. How many will he have to take out of his pocket to ensure that he has taken out at least one of each color?
To ensure that the boy has taken out at least one of each color, let's consider the worst-case scenario, which means assuming that he will first take out the maximum number of marbles of a single color.
In this case, the boy will have to take out all of the red marbles (3) before he can be sure that he has taken out at least one of each color.
Therefore, he will have to take out a minimum of 3 marbles.