In a business class,40% of the students have never taken a statistics class,15% have taken only one semester of statistics,and the rest have taken two or more semesters of statistics.The professor randomly assigns students to groups of three to work on a project for the course.What is the probability that the first group mate you meet has studied two or more semesters of statistics?
A)0.55
B)0.85
C)0.15
D)0.45
E)0.60

Question

Quizplus · Accepted Answer

Let's assume there are 100 students in the business class.
40 students have never taken a statistics class.
15 students have taken only one semester of statistics.
So, the remaining students are 100 - 40 - 15 = 45.
Therefore, 45 students have taken two or more semesters of statistics.
Now, when the professor randomly assigns groups of three, the first person you meet can be any of the 100 students with equal probability.
Out of the 100 students, 45 have taken two or more semesters of statistics. Therefore, the probability that the first person you meet has studied two or more semesters of statistics is 45/100 or 0.45.
Hence, the answer is D.

In a Business Class,40% of the Students Have Never Taken