1. Probability Practice

2. The Flyers and Rangers play a best of 3 game series
The Flyers and Rangers play a best of 3 game series. Whoever wins 2 games wins the series. Make a tree diagram and determine the probability that the Flyers win. (each team has an equal chance of winning – leave your answer as a decimal.) .5
0.0

3. The Flyers and Rangers play a best of 3 game series
The Flyers and Rangers play a best of 3 game series. Whoever wins 2 games wins the series. Make a tree diagram and determine the probability that the series goes to 3 games and the Rangers win (each team has an equal chance of winning – leave your answer as a decimal.)
.25
0.0

4. The Flyers and Rangers play a best of 3 game series
The Flyers and Rangers play a best of 3 game series. Whoever wins 2 games wins the series. Make a tree diagram and determine the probability that the winning team wins the first game. (each team has an equal chance of winning – leave your answer as a decimal.)
.375
0.0

5. It is estimated that 4% of people who spend time in the woods will get Lyme disease. Of the people with Lyme disease, the test to determine if you have it will give a positive reading 97% of the time. Of people who do not have Lyme disease, the same test will give a negative rating 92% of the time. Make a tree diagram for this problem and then determine the probability that the person get a positive reading.
.116
0.0

6. It is estimated that 4% of people who spend time in the woods will get Lyme disease. Of the people with Lyme disease, the test to determine if you have it will give a positive reading 97% of the time. Of people who do not have Lyme disease, the same test will give a negative rating 92% of the time. Make a tree diagram for this problem and then determine the probability that the person has Lyme’s disease, but has a negative reading on the test.
.0012
0.0

7. It is estimated that 4% of people who spend time in the woods will get Lyme disease. Of the people with Lyme disease, the test to determine if you have it will give a positive reading 97% of the time. Of people who do not have Lyme disease, the same test will give a negative rating 92% of the time. Make a tree diagram for this problem and then determine the probability that the person does not have Lyme’s disease, but has a positive reading on the test.
.077
0.0

8. A sports locker at school contains 6 basketballs, 9 footballs, and 5 volleyballs. During a sports lesson, a teacher chooses two balls from the locker at random, without replacement. Draw a tree diagram and find the probability that the teacher chooses two basketballs. (give your answer as a fraction)
3/38
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9. A sports locker at school contains 6 basketballs, 9 footballs, and 5 volleyballs. During a sports liesson, a teacher chooses two balls from the locker at random, witout replacement. Draw a tree diagram and find the probability that the teacher chooses one basketball and one football. (give your answer as a fraction)
27/95
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10. A sports locker at school contains 6 basketballs, 9 footballs, and 5 volleyballs. During a sports liesson, a teacher chooses two balls from the locker at random, with replacement. Draw a tree diagram and find the probability that the teacher chooses two of the same type of ball. (give your answer as a fraction)
61/190
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11. A writer has a bad habit of holding onto pens that stop working
A writer has a bad habit of holding onto pens that stop working. He has 3 pens in his briefcase. The firs pen he tries has an 80% chance of working. The second pen has a 60% chance of working and the 3rd pen has a 40% chance of working. If a pen stops working, he’ll try another pen. Draw a tree diagram that illustrates this problem and determine the probability that at least one pen works.
.952
0.0

12. A writer has a bad habit of holding onto pens that stop working
A writer has a bad habit of holding onto pens that stop working. He has 3 pens in his briefcase. The firs pen he tries has an 80% chance of working. The second pen has a 60% chance of working and the 3rd pen has a 40% chance of working. If a pen stops working, he’ll try another pen. Draw a tree diagram that illustrates this problem and determine the probability that he will have to choose 3 pens.
.032
0.0

13. 80 students were asked what type of television programme they had watched the previous evening watched sports, 42 watched news, 50 watched drama, 10 watched all three types. 7 watched sports and news only, 12 watched news and drama only, 14 watched sports and drama only. Draw a Venn Diagram and determine the number of students who did not watch neither sports, nor drama, nor News. 6
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14. 80 students were asked what type of television programme they had watched the previous evening watched sports, 42 watched news, 50 watched drama, 10 watched all three types. 7 watched sports and news only, 12 watched news and drama only, 14 watched sports and drama only. Draw a Venn Diagram and determine the probability that a student watched drama only. (Give your answer as a fraction)
7/40
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15. 80 students were asked what type of television programme they had watched the previous evening watched sports, 42 watched news, 50 watched drama, 10 watched all three types. 7 watched sports and news only, 12 watched news and drama only, 14 watched sports and drama only. Draw a Venn Diagram and determine the probability that a student watched sports given that the student also watched news.
17/42
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16. 80 students were asked what type of television programme they had watched the previous evening watched sports, 42 watched news, 50 watched drama, 10 watched all three types. 7 watched sports and news only, 12 watched news and drama only, 14 watched sports and drama only. Draw a Venn Diagram and determine the probability that a student watched at least 2 types of programmes.
43/80
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