11. You are taking a multiple choice examination that has 20 questions in a particular section
with 5 possible answers for each question. You did not study for the test and you
guessed the answers. The probability that you will get at least 50% of the problems
correct by guessing is
(a) 0.32%
(b) 0.26%
(c) 60.5%
(d) 53.32%
(e) None of the above
12. Statistics show that one‐half of all fatal automobile accidents involve drunk driving. Of
the next 5 fatal car accidents on the highway of a city, the probability that at least 2 of
the accidents were caused due to drunk driving:
(a) 0.8456
(b) 0.7030
(c) 0.8125
(d) 0.4717
(e) 0.6544
13. A recent statistics show that that the number of alcohol related accidents has gone
down. Suppose that approximately 40% of all fatal automobile accidents involve drunk
driving. Of the next 5 fatal car accidents on the highway of a city, the probability that at
least one accident was caused due to drunk driving:
(a) 0.0778
(b) 0.3530
(c) 0.9222
(d) 0.9033
(e) 0.9122
14. A communication satellite system can function if at least 2 of the 5 power sources in the
system work properly. Each power source works independently with probability 0.90.
The probability of the satellite system functioning properly:
(a) 0.0009
(b) 0.9300
(c) 0.9995
(d) 0.9033
(e) None of the above