Probability

Probability

Calculate the probability of events!!!

Multiple Choice

Twenty students are selected at random from a group of 500 students that took a common test. Of those twenty, six students received an A on the test.

Based on the given, if a student from the entire group is picked at random, what is the probability that he or she scored a grade lower than A?

• 7/10

• 7/20

• 2/5

• 3/10

Multiple Choice

An experiment was conducted by tossing a coin 90 times. The coin landed on heads 35 times and on tails 55 times.

Based on this experiment, what is the experimental probability of the coin landing on heads?

• 7/11

• 1/3

• 7/18

• 1/18

Multiple Choice

B is an event in a sample space S.

Which of the following could be the value of P(B)?

• 5/3

• 1.1

• -0.9

• 0.99

Multiple Choice

A jar contains 6 red marbles, 3 white marbles, and 1 blue marble.

Two marbles are randomly picked without the first marble being replaced.

What is the probability that both marbles are white?

• 1/5

• 1/15

• 3/10

• 9/100

Multiple Choice

The tree diagram below illustrates the probabilities involving two picks from a bag of marbles without replacement.

The probability that the first marble is black and the second marble is green is ________?

• 7/18

• 3/4

• 5/18

• 2/9

Multiple Choice

A jar contains 6 red marbles, 3 white marbles, and 1 blue marble.

Two marbles are randomly picked one after the other without the first marble being replaced.

Which of the following is a correct way to calculate the value of P(White, then Red)?

• 3/10 x 6/10

• 3/7 x 6/7

• 3/10 x 2/9

• 3/10 x 6/9

Multiple Choice

An experiment consists of tossing an unbalanced coin twice. The tree diagram below shows the possible outcomes and their probabilities.

If this coin is tossed twice, what is the probability that tails is tossed both times?

• 0.49

• 0.14

• 1.4

• 0.98

Multiple Choice

An experiment involves tossing a balanced coin and rolling a fair die.

What is the probability of the coin landing on heads and the face up on the die showing a 2 or a 3?

• 1/4

• 2/3

• 1/6

• 1/2

Multiple Choice

A and B are two independent events with P(A) = 0.2 and P(B) = 0.5.

What is the value of P(A and B)?

• 0,7

• 0,3

• 0,1

• 1

Multiple Choice

The list below shows the number of children of 20 families selected randomly from the 200 families living in a neighborhood.

0 2 5 4 3 1 0 2 3 6

2 2 1 0 3 2 1 4 5 1

Based on this list, if a family from these 200 is picked at random, what is the probability that it has less than 3 children?

• 3/5

• 4/5

• 2/5

• 3/10

Multiple Choice

A password is formed using three different letters (A – Z). If such a password is formed at random, what is the probability that it will start with the letter Z?

• 1/13

• 2/13

• 1/650

• 1/26

Multiple Choice

Seven identical cards are numbered from 1 to 7. An experiment consists of drawing two cards one after the other without replacement and recording the card numbers.

What is the probability that both numbers selected are even numbers?

• 1/7

• 3/7

• 9/49

• 1/21

Multiple Choice

Gerald has only white, blue, and grey shirts in his wardrobe. A shirt is picked at random from the wardrobe. The probability that the shirt is white is 0.4. The probability that the shirt is grey is 0.1.

What is the probability that the shirt is blue?

• 0.2

• 0.5

• 0.1

• 0.6

Multiple Choice

There are 9 lemons, 8 oranges, and 4 grapefruits in a basket of fruits. A fruit is picked randomly.

What is the probability that the fruit picked is an orange?

• 1/8

• 1/3

• 8/13

• 8/21

Multiple Choice

The sample space of an experiment consists of n equally likely outcomes, 12 of which are considered favorable for an event B. If P(B) = 0.03, then the value of n is _______?

• 200

• 400

• 12

• 120

Multiple Choice

A group of 10 managers consists of 6 women and 4 men. A committee of 3 managers is selected at random.

What is the probability that at least one manager selected is a woman?

• 2/5

• 3/5

• 19/20

• 29/30

Multiple Choice

Two students are picked at random from a group of 15 students. The group consists of 6 girls and 9 boys.

What is the probability that both students picked are girls?

• 3/5

• 1/7

• 1/9

• 4/25