Answer
$52$
Work Step by Step
If the marbles he picked are all the same color, they are all red.
As we already know (see Exercise 40) the number of all possible outcomes is 56, and the number of possible outcomes in the event that all the marbles he picked are red is 4.
Therefore the number of outcomes in the event that the marbles Pablo picks are not all the same color is $56-4=52$
