Question

A group of applicants for a position consists of 8 people who are qualified and 7 whoa are not. If we select two people at random to be interviewed (obviously without replacement), find the probability that we get:
a. two qualified people
b. one qualified and one unqualified person (think about different ways this could happen).
c. At least ONE qualified person. Hint: Use the complement law.

for a)i got the answer 4/15. 8/15*7/14
for b) i got the same answer

for c) the prob of picking both unqualified is 7/15*6/14= 1/5 so using complement would mean that i would take 1-1/5 to get 4/5???

Answer 1

The first two answers are right.

For C, to get "At least ONE qualified person," you want the probability for one qualified person <I>plus</I> the probability for two qualified persons.

I hope this helps. Thanks for asking.