Lesson 4: Conditional Probability Answers

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?

Seventy-five percent of the flowers in the arrangement are roses and the rest are tulips. Of the tulips, 50 percent are pink.To the nearest whole percent, what is the probability that a randomly chosen flower from the arrangement is a pink tulip?

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?

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?

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

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.

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.

Use the Venn diagram to calculate probabilities.