A tray of electronic components contains 17 components, 5 of which are defective. If 4 components are selected, what is the possibility of each of the following? (Round your answers to five decimal places.)
(a) that all 4 are defective
(b) that 3 are defective and 1 is good
(c) that exactly 2 are defective

Question

A tray of electronic components contains 17 components, 5 of which are defective. If 4 components are selected, what is the possibility of each of the following? (Round your answers to five decimal places.) 
(a) that all 4 are defective
 (b) that 3 are defective and 1 is good
 (c) that exactly 2 are defective

anonymous · Answer

there are a couple ways to do this
probably the simplest is to use as your denominator $\binom{17}{4}$ the number of ways to choose 4 out of the 17

anonymous · Answer

then for the numerator, the first one should be $\binom{5}{4}$ the number of ways to choose 4 out of the 5 defective