Answer:
Below.
Step-by-step explanation:
The total number of marbles is 12.
Part A.
Prob(Red marble) = 5/12.
Part B.
Prob(pick 3 red marbles without replacement) = 5/12 * 4/11 * 3/10 = 1/22.
Part C.
The probability of the first being red is 5/12 because there are 5 red out of a total of 12 marbles. After that there are only 4 marbles and the total is 11 ( 1 marble less). Finally on the 3rd pick there are 3 red and a total of 10. WE then multiply these 3 probabilities.