Conditional Probability — Quiz Answers

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. What is the probability that both of Eduardo’s partners for the group project will not be boys?

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?

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.

A survey of the 12 th grade students at Gaffigan High School found that 84 percent of the seniors have their driver’s licenses, 16 percent of seniors take the bus every day to school, and 14 percent of the seniors have driver’s licenses and take the bus to school every day. To the nearest whole percent, what is the probability that a senior takes the bus to school every day, given that he or she has a driver’s license?

If events cap A and cap b are independent, and the probability that event cap A occurs is 83 percent , what must be true?

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?

A study found that 23 percent of the cars manufactured last year were SUVs, 13 percent of the cars manufactured were white, and 2 percent of the cars manufactured were white SUVs. To the nearest whole percent, what is the probability that a car is an SUV, given that it is white?

A prize bag contains four country music CDs, eight pop music CDs, and five classic rock CDs. What is the probability of pulling out a classic rock CD and then, without replacing it, pulling out a country music CD? Express your answer in decimal form, rounded to the nearest hundredth.

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