Answer
$56$
$4$
Work Step by Step
We simply count how many ways Pablo can choose three marbles from a bag of 8 marbles.
That is $C(8,3)=\frac{8!}{5!*3!}=\frac{8*7*6*5*4*3*2*1}{5*4*3*2*1*3*2*1}=7*8=56$
To count the number of outcomes in which all of the marbles he picks are red, we count how many ways he can pick 3 marbles from the 4 marbles that are red.
That is $C(4,3)=4$
