Question

A jar contains 8 marbles 5 of which are purple and 3 that are yellow.

a. What is the probability that you pick a yellow marble, put it back and pick a purple marble? b. Without replacement what is the probability that you pick two yellow marbles? c. without replacement what is the probability that you pick a green marble followed by a purple marble?

Answer 1

a) Probability that we pick a yellow marble, put it back and pick a purple marble is computed here as:
= P(Yellow)*P(purple)

= (3/8)*(5/8)

= 0.234375

Therefore 0.234375 is the required probability here.

b) As we are drawing marbles without replacement here, the probability that we pick two yellow marbles is computed here as:

= Number of ways to select 2 yellow marbles from 3 yellow marbles / Number of ways to select 2 marbles from 8 marbles

= (3c2) / (8c2)

= 3 / 28

= 0.1071

Therefore 0.1071 is the required probability here.

c) The probability that we pick a green marble followed by a purple marble is 0 as there is no green marble out of the total marbles here. Therefore 0 is the required probability here.