Exercise 2.
Suppose that a room contains n people. What is the probability that at least two of them have a
birthday on same month? Make a plot of probability vs number of people and find out for how many
people does the probability becomes greater than 0.5 and 0.9.
Sixty percent of the students at a certain school wear neither a ring nor a necklace. Twenty percent
wear a ring and 30 percent wear a necklace. If one of the students is chosen randomly, what is the
probability that this student is wearing
Sun | Mon | Tue | Wed | Thu | Fri | Sat |
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1 | 2 | 3 | 4 | 5 | 6 | 7 |
8 | 9 | 10 | 11 | 12 | 13 | 14 |
15 | 16 | 17 | 18 | 19 | 20 | 21 |
22 | 23 | 24 | 25 | 26 | 27 | 28 |
29 | 30 | 1 | 2 | 3 | 4 | 5 |