Bluebook SAT Test Probability and Conditional Probability 7

Question 1

A jar contains 4 red, 3 blue, and 5 green marbles. One marble is drawn at random. What is the probability of drawing a red or blue marble?

Accepted Answer

7/12

Answer

4/12

Answer

3/12

Answer

1/2

Question 2

The two-way table shows 240 students by grade and lunch preference.

Hot Lunch  Packed Lunch
Grade 7              60            40
Grade 8              70            70

A Grade 8 student is selected at random. What is the probability the student prefers hot lunch?

Accepted Answer

1/2

Answer

7/12

Answer

5/12

Answer

7/24

Question 3

A fair coin and a fair die are both tossed. What is the probability of getting heads and an even number?

Accepted Answer

1/4

Answer

1/2

Answer

1/6

Answer

1/3

Question 4

A test has 50 questions: 20 multiple choice, 20 short answer, and 10 essay. If one question is picked at random, what is the probability it is NOT an essay question?

Accepted Answer

4/5

Answer

1/5

Answer

3/5

Answer

2/5

Question 5

Events M and N are mutually exclusive with P(M) = 0.25 and P(N) = 0.40. What is P(M or N)?

Accepted Answer

0.65

Answer

0.10

Answer

0.15

Answer

0.75

Question 6

Of 80 cars in a lot, 30 are red and 20 have sunroofs. If 10 cars are both red and have sunroofs, what is the probability a randomly chosen car is red OR has a sunroof?

Accepted Answer

1/2

Answer

3/8

Answer

5/8

Answer

3/4

Question 7

A survey table shows 300 adults categorized by income level and vacation frequency.

Vacation yearly  No vacation
High income              90           30
Middle income            60           60
Low income               30           30

Given that an adult takes a yearly vacation, what is the probability they have a high income?

Accepted Answer

1/2

Answer

1/3

Answer

3/10

Answer

2/5