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Discussion 1 of Week 2, Jan 26
1.
A trucking firm has a contract to ship a load of goods from city W to city Z. There
are no direct routes connecting W to Z, but there are 6 roads from W to X and 5
roads from X to Z. How many total routes are there to be considered?
2.
Consider the word “TENNESSEE”. Calculate the number of ways to arrange the
letters in the word.
3.
By accident, a chemist combined two laboratory substances that yielded a
desirable product. Unfortunately, she did not record the names of ingredients.
There are forty substances available in the lab. If the two in question must be
located by successive trial and error experiments. What is the maximum number
of tests that might be made?
4.
Suppose, the order in which the ingredients are mixed is important what is the
maximum number of tests that might be made?
5.
A major league baseball team typically has 25 players. A line up consists of nine
of these players in a particular order. Calculate the number of possible lineups.
6.
An NBA basketball team typically has 12 players. A starting team consists of 5 of
these players in the particular order. In how many ways can you form the starting
team?
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View Full Document Disucussion I Answer
40
2
25
9
12
5
65
1.
11
9!
2.
1!4!2!2!
40
40!
3.
2
2!38!
40!
4.
P
38!
25!
5.
P
16!
12!
6.
P
7!
GE331 Discussion II of Week 3,Feb 02,2009
1.
Many companies are testing prospective employees for drug use, with the intent of
improving efficiency and reducing absenteeism, accidents, and theft. Opponents
claim that this procedure is creating a class of unhirables and that some persons may
be placed in this class because the tests themselves are not 100% reliable. Suppose a
company uses a test that is 98% accurate  that is, it correctly identifies a person as a
drug user or nonuser with probability .98  and to reduce the chance of error, each job
applicant is required to take two tests. If the outcomes of the two tests on the same
person are independent events, what are the probabilities of these events?
a.
A nonuser fails both tests.
b.
A drug user is detected (i.e., he or she fails at least one test).
c.
A drug user passes both tests.
2.
A college student frequents one of two coffee houses on campus, choosing Starbucks
70% of the time and Peetes 30% of the time. Regardless of where she goes, she buys
a cafe mocha on 60% of her visits.
a.
The next time she goes into a coffee house on campus, what is the probability
that she goes to Starbucks and orders a cafe mocha?
Are the two events in part a independent? Explain.
c.
If she goes into a coffee house and orders a cafe mocha, what is the
probability that she is at Peetes?
3.
A smokedetector system uses two devices, A and B. If smoke is present, the
probability that it will be detected by device A is .95; by device B, .98; both
devices, .94.
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This note was uploaded on 09/08/2009 for the course GE 331 taught by Professor Negarkayavash during the Spring '09 term at University of Illinois at Urbana–Champaign.
 Spring '09
 NegarKayavash

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