Question

5. Consider the probabilities in problem 4. The probability that a randomly selected single
book purchase will not be for a work of fiction is
(a) 0.80
(b) 0.25
(c) 0.20
(d) 0.30
(e) 0.75

6. Two dice are rolled. Suppose A is the event the sum of the numbers on the top faces is
even, and B is the event that one of the dice shows the number “1.” The probability of
event B is
(a) 1/2
(b) 18/36
(c) 12/36
(d) 11/36
(e) 1/3
3

7. A child is playing with three dice: red, green, and blue. The probability that she will roll a
5 on the red, a 4 on the green, and a 3 on the blue is:
(a) 1/2
(b) 1/36
(c) 1/216
(d) 4/36
(e) 1/3

Answer 1

(6) 11/36
(7) 1/216

Answer 2

6. No, either-or probabilities are found by adding the individual probabilities.

P = P(1) + P(1) = ?

7. If the events are independent, the probability of both/all events occurring is determined by multiplying the probabilities of the individual events.

Answer 3

Well, there are 11 possible combinations that one of two dices rolls 1.

i.e. (1,1) (1,2),....(2,1), (3,1)....

probability for single event P(1)= 1/36.
then Adding all 11 events is

P = P(1) + P(1) +P(1) +...... 11 times
= 1/36 + 1/36 + 1/36 +.....
=11/36.

additionally probability for event A is 18/36

Answer 4

Consider each die separately.

The P for die 1 to have a 1 = 1/6

The P for die 2 to have a 1 = 1/6

You want either one or the other of the dice to show a 1. Either-or probabilities are found by adding the individual probabilities.

Answer 5

rolling two dice together, what is the probability of getting (6,6)?