Thread: checking my answers !! please have a look!!

problem 1:
A card is drawn at random from a standard deck of 52 cards. What is the probability
of drawing
(a) a king of spades?
(b) a king?
(c) not a king?
(d) a diamond?
(e) a face card (jack, queen, or king)?

answer :
a) 1/52
b)4/52
c)48/52
d)12/52
c)12/52

second problem :
It is believed that 2 genes A and B may play some part in the susceptibility of an
individual to a disease. Of 100 patients investigated, 17 carry gene A, 33 carry gene
B and 67 carry neither. Find the probability that a patient carries only gene A, only
gene B or both.
answer :
i said if 67 patients don't have neither A or B, implies that 33 have wether A or B, and we know that 33 patient has gene B and 17 has A, which means the ones who only have gene B is 33-17=16. also 0 patients have only gene A. and then 17 has has both A and B!
conclusion :
probability of patient:
with only gene A is 0
with only B is 16/100
with both is 17/100

thanks a lot in advance!!

There are 13 diamonds. A23456789TJQK.

Your answers are right but DON'T FORGET TO SIMPLIFY!!!