Question

2.         Earlier this semester we had a problem with birds with sore throats. I own the pet

store that has these birds and I need to get them some medical treatment. When I look in the phone book, I find four veterinarian hospitals/clinics with doctors that treat birds. They are:

                  a.         Animal Lover’s Animal Hospital (A L A H)

b.   Victor’s Vetnarian Clinic (V² C)

c.   The Home for Wobbly Wings (H W²);   and

d.   Rudolph’s Tiny Animal Shelter (R A T S) (specializes in pigmy reindeer)

The phone book does not list a phone number for any of these organizations. However, it does list 50 separate phone numbers for “doctors” who treat birds, but only lists the single title “bird-doctor” and a phone number beside each number. It does not indicate any more information than that. These 50 doctors work in the four organizations listed above, but I cannot tell which organization each belongs to, because all the phone book has is a number. Some of the doctors have vaccines that heal the sore throats; some of them do not. Additionally, one of the doctors, one Margaret Mbitu (M²), has the vaccine but is afraid of birds and won’t treat them.

The distribution of doctors in the four hospitals/clinics is as follows:

            A L A H                         V² C                            H W²                             R A T S

Doctors w/ vaccine                 0                           4                                    6                                        5

   w/ vaccine but afraid                                              1

Doctors w/out vaccine                 8                            8                                      6                                     12

If I randomly dial one of the doctor’s numbers, what is the probability that:

a.         I get a doctor working with A L A H?

b.         I get a doctor working with A L A H or V² C?

c.         I get a doctor who does not have the vaccine?

d.         I get a doctor working with H W²      or one who does have the vaccine?

e.         I get a doctor who, for whatever the reason, is unable to give the vaccine?

f.          I get a doctor who has the vaccine?

If I dial two doctors’ numbers in succession, making sure that I do not accidentally re-dial the first (this means that, after the first number is dialed, it is removed from the number pool), what is the probability that:

a.         I will get two doctors that do not have the vaccine?

b.         I will not get a doctor with the vaccine on the first call and do get a doctor

with the vaccine on the second call?

Answer 1