Review for probability test tomorrow.

1. Twelve people, including you, are members of a choir. The choir director is
going to choose three members to attend a workshop. The probability you and
two other members will be chosen is:
(a) (b) (c) (d)

2. Rex is playing a guessing game. The probability he will guess each question
correct is 0.3. What is the probability he will guess exactly 5 out of 10
questions correctly?
(a) 0.15 (b) 0.10 (c) 0.29 (d) 0.80

3. You choose four digits from the numbers 0-9 (ten digits in total), with no
repeated digits. To win a prize, only two of your numbers need to match the
four selected by a computer. The probability, correct to the nearest hundredth,
that you will win a prize is:

4. The serial number of a $10 bill contains 8 digits. If your $10 bill contains the
digit 7 at least once, you win a prize. What is the probability that your $10 bill
will win?

5. Jeff takes a lunch to school on two days, and on the other three days he buys it.
If he takes lunch he is late for his period 4 class 15% of the time, but if buys it
he is late 35% of the time.
(a) What is the probability that Jeff arrives on time?
(b) If Jeff was late, what is the probability that he took his lunch to school?