Question

There are 50 students in a class and the professor chooses 15 students at random. what is the probability that you or your friend joe are among the chosen students?

Answer 1

Try this option (see the attachment). Make design according own requirements.
Note, that the description and details are under green line.

Answer: 0.030921

Answer 2

Answer:

30% probability that Joe is among the chosen students.

Step-by-step explanation:

A probability is the number of desired outcomes divided by the number of total outcomes.

The order in which the students are chosen is not important, so the combinations formula is used to solve this question.

Combinations formula:

$C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

Desired outcomes:

Joe

14 remaining students, from the remaining 49. So

$D = C_{49,14} = \frac{49!}{14!(49-14)!} = 675248872536$

Total outcomes:

15 students, from a set of 50. So

$T = C_{50,15} = \frac{50!}{15!(50-15)!} = 2.2508296 \times 10^{12}$

Probability

$p = \frac{D}{T} = \frac{675248872536}{2.2508296 \times 10^{12}} = 0.3$

30% probability that Joe is among the chosen students.