Find the probability of selecting a blue marble or an orange marble from a bag containing 10 red, 12 blue, and 11 orange marbles.

Question

Find the probability of selecting a blue marble or an orange marble from a bag containing 10 red, 12 blue, and 11 orange marbles.

I believe this is an Exclusive event

P(A) = blue marbles = 12/33 = 4/11
P(B) = orange marbles = 11/33 = 1/3
P(A and B) = P(A + B) = 4/11 + 1/3
P(A and B) = 23/33

This seems too easy. Am I correct?

Answer 1

23/33 is correct but to be precise you should write it as P(A or B) not AND