Question

There are 6 black balls and 5 red balls in an urn. If 4 balls are drawn without replacement, what is the probability that exactly 2 black balls are drawn? Express your answer as a fraction or a decimal number rounded to four decimal places.

Answer 1

There are a total of 6+5=11 balls in the urn.

Total number of ways of drawing 4 balls without replacement is

Number of ways of getting 2 black balls (and hence 2 red balls) is

the probability that exactly 2 black balls are drawn is

ans: the probability that exactly 2 black balls are drawn is 0.4545 (or 5/11)