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(B ∩ R) = The probability that the first ball chosen is black and the second ball chosen is red is about percent.

Answer 1

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.

Answer 2

black ball and red ball

8 out of 12 x 4 out of 11

`(8)/(12)` x
`(4)/(11)`

=
`(8(4))/(12(11)) = (8)/(3(11)) = (8)/(33)` = 0.24 = 24%

Answer: 24%