See Problem 4.

S and T are mutually exclusive events. Find P(S or T).

21. P ( S ) = 5 8 , P ( T ) = 1 8 p open s close equals , 5 eighths , comma p open t close equals , 1 eighth
22. P ( S ) = 3 5 , P ( T ) = 1 3 p open s close equals , 3 fifths , comma p open t close equals , 1 third
23. P ( S ) = 12 % , P ( T ) = 27 % p open s close equals 12 percent comma p open t close equals 27 percent
24. Population About 30% of the U.S. population is under 20 years old. About 17% of the population is over 60. What is the probability that a person chosen at random is under 20 or over 60?

See Problem 5.

A standard number cube is tossed. Find each probability.

25. P(3 or odd)
26. P(4 or even)
27. P(even or less than 4)
28. P(odd or greater than 2)
29. P(odd or prime)
30. P(4 or less than 6)

B Apply

31. Think About a Plan A multiple-choice test has four choices for each answer. Suppose you make a random guess on three of the ten test questions. What is the probability that you will answer all three correctly?
    • Is each guess a dependent event or an independent event?
    • What is the probability that a random guess on one question will yield the correct answer?
32. Suppose a number from 1 to 100 is selected at random. What is the probability that a multiple of 4 or 5 is chosen?

Statistics The graph below shows the types of jobs held by people in the U.S. Find each probability.

U.S. Employment, by Occupation

SOURCE: U.S. Census Bureau

33. A person is in a service occupation.
34. A person is in service or sales and office.
35. A person is not in production, transportation, and material moving.
36. A person is neither in service nor in sales and office.

A jar contains four blue marbles and two red marbles. Suppose you choose a marble at random, and do not replace it. Then you choose a second marble. Find the probability of each event.

37. You select a blue marble and then a red marble.
38. You select a red marble and then a blue marble.
39. One of the marbles you select is blue and the other is red.
40. Both of the marbles you select are red.

For each set of probabilities, determine if the events A and B are mutually exclusive.

41. P ( A ) = 1 2 , P ( B ) = 1 3 , P ( A  or  B ) = 2 3 p open eh close equals , 1 half , comma p open b close equals , 1 third , comma p open eh , or b close equals , 2 thirds
42. P ( A ) = 1 6 , P ( B ) = 3 8 , P ( A  or  B ) = 13 24 p open eh close equals , 1 sixth , comma p open b close equals , 3 eighths , comma . p open eh , or b close equals , 13 over 24

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