Mrs. Burke’s physics class has 109
students, classified by academic year and major, as illustrated in the table. Mrs. Burke randomly chooses one student to collect yesterday’s work.
Mrs. Burke’s Physics Class
Academic Year Physics Majors Non-Physics Majors
Freshmen 13
14
Sophomores 13
17
Juniors 14
13
Seniors 9
16
Step 2 of 2 : What is the probability that she selects a freshman, given that she chooses a physics major? Enter a fraction or round your answer to 4
decimal places, if necessary.
First, we need to calculate the total number of physics majors in the class by adding up the physics majors in each academic year:
13 + 13 + 14 + 9 = 49
Next, we need to calculate the probability of selecting a freshman who is also a physics major:
Probability = (Number of physics major freshmen) / (Total number of physics majors)
Probability = 13 / 49
Probability = 0.2653 or 26.53%