Can you explain how to find probability?

Question

A class contains 7 women and 7 men.  Suppose that we choose three random students. How many ways can we choose exactly 1 woman?

Answer 1

the probabilities that a batch of 4 computers will contain 0, 1, 2, 3, and 4 defective compiters are 0.4094, 0.4094, 0.1536, 0.0256, and 0.0016 respectively.  Fond the standard deviation for the probability distribution.  Round to the nearest hundredth.

Answer 2

men                             women

n=7                              n=7

r = 2                             r = 1

total outcomes= n = 14C3 = 364

favourable outcomes = m =  7C1 X 7C2

                                            7  X 21

                                              147

probability = m/n = 147/ 364

                 p=  0.403

                               answer

Answer 3

a balanced die is rolled 6 times what is the conditional probablity of getting exactly2 sixes.

a)given exactly 2 aces.

b)given at least 2 aces.