A bag contains 7 white balls, 5 black balls, and 4 red balls. One by one, three balls are drawn out without replacement. What is the probability that the third ball is red? Options.
A) 1/2
B) 1/4
C) 3/8
D) 5/12
E) 2/5
The probability for each ball to be drawn third is equal.   Then the probability a red ball is drawn third is 4/16 = 1/4.   The answer is 1/4.
<result>B</result>
A bag contains 7 white balls, 5 black balls, and 4 red balls. One by one, three balls are drawn out without replacement. What is the probability that the third ball is red?