Conditional Probability Answers

A survey of the 12th grade students at Gaffigan High School found that 84% of the seniors have their driver’s licenses, 16% of seniors take the bus every day to school, and 14% of the seniors have driver’s licenses and take the bus to school every day.

Nadia’s bookshelf contains 10 fiction books, two reference books, and five nonfiction books.What is the probability that she randomly picks up a reference book and then, without replacing it, picks up a nonfiction book?

Use the Venn diagram to calculate probabilities.

Use the Venn diagram to calculate probabilities.

A bag contains one red pen, four black pens, and three blue pens. Two pens are randomly chosen from the bag and are not replaced.To the nearest hundredth, what is the probability that a black pen is chosen first and then another black pen is chosen?

A hat contains slips of paper with the names of the 26 other students in Eduardo’s class on them, 10 of whom are boys. To determine his partners for the group project, Eduardo has to pull two names out of the hat without replacing them.

Lori downloaded all the pictures she took at Rita’s wedding into a single computer folder. She took 86 of the 134 pictures with her camera and the remainder of them with her cell phone. Of the pictures Lori took with her cell phone, one out of every five was blurry.

Twenty-two percent of the large pieces of mail that Rachel received this week were magazines and the rest were catalogs. Of the catalogs, 36 percent were for clothing.To the nearest whole percent, what is the probability that a randomly chosen large piece of Rachel’s mail was a clothing catalog?

If events A and B are independent, what must be true?

Lola pulls two marbles from a bag containing four red marbles, four blue marbles, and 12 yellow marbles without replacing them.What is the probability that she pulled out a red marble first and a yellow marble second? Express your answer in decimal form, rounded to the nearest hundredth.

In the drawing, six out of every 10 tickets are winning tickets. Of the winning tickets, one out of every three awards is a larger prize.What is the probability that a ticket that is randomly chosen will award a larger prize?

Twenty-five bakery customers were surveyed to determine if they like cake or pie. The results are shown in the Venn diagram.

Hiro has a stack of cards with one number from the set 1, 1, 2, 2, 3, 3, 3, 4 written on each card.What is the probability that he pulls out a 3 first and then pulls out a 2 without replacing them?

If events A and B are independent, and the probability that event A occurs is 83%, what must be true?