Question 593116
1. There are 4 red marbles out of a total of 13 marbles.
So P(1 red) = 4/13

2. The probability of selecting 1 red, 1 yellow and 1 brown in succession is the product of the individual probabilities.
P(red) = 4/13 from 1.
For the selection of the yellow marble, there are still 2 yellow marbles and one fewer total marbles to choose from: 
P(yellow) = 2/12
Likewise, P(brown) = 7/11
So P(1r,1y,1b) = 4/13*2/12*7/11 = 0.0326