Question

Your teacher has 50 pencils. 9 of the pencils are green, 10 are yellow, 7 are

blue and the rest are red. Once a pencil is picked, assume it is not given
back to the teacher. What is the probability that the first 3 students pick a
yellow pencil, a blue pencil and a red pencil in that order? Is this a
dependent or independent event? *
A. Independent, 1/70
B. Dependent, 1/70
C. Independent, 41/3125
D. Dependent, 41/3125

Answer 1

B. Dependent, 1/70

Explanation:

The probability that the first pencil is yellow is 10/50.

There are now 49 pencils, so the probability that the second pencil is blue is 7/49.

There are now 48 pencils, so the probability that the third pencil is red is 24/48.

The total probability is (10/50) (7/49) (24/48) = 1/70.

Since the pencils aren't replaced after selection, each event changes the probability of the next, so the events are dependent.