Question

A box contains four red balls and eight black balls. Two balls are randomly chosen from the box, and are not

replaced. Let event B be choosing a black ball first and event R be choosing a red ball second.
What are the following probabilities?
P(B) =
P(R B) =
P(
BR) =
The probability that the first ball chosen is black and the second ball chosen is red is about percent.

Answer 1

Explanation:

Total balls = 12

Probability of 2 black balls = 2/ 8 = 1/4

Probability of 2 red balls = 2/4 = 1/2

Probability of both red and black = 2/12 = 1/6

Answer 2

P(B) = 8/12

P(R | B) = 4/11

P(B ∩ R) = 8/33

The probability that the first ball chosen is black and the second ball chosen is red is about 24% percent.

Explanation: