Answer to Question #220861 in Statistics and Probability for Ann

Question

Among 18 computers, 12 are in 2working order and six are defective.  How many samples of 4 are possible, selected without replacement and without regard to order, wherein all are defective?

Answer 1

$$\dbinom{12}{0}\dbinom{6}{4}=1(15)=15$$

15 samples are possible.