Five juniors and four seniors have applied for two open student council positions. School administrators have decided to pick the two new members randomly. What is the probability they are both juniors or both seniors?
A) 0.506
B) 0.722
C) 0.444
D) 0.569
E) 0.395

Question

Quizplus · Accepted Answer

The total number of ways to select 2 students out of 9 is: 
9C2 = (9*8)/(2*1) = 36
The number of ways to select 2 juniors out of 5 is:
5C2 = (5*4)/(2*1) = 10
The number of ways to select 2 seniors out of 4 is:
4C2 = (4*3)/(2*1) = 6
Therefore, the total number of ways to select 2 students where both are juniors or both are seniors is:
10 + 6 = 16
The probability of selecting 2 students where both are juniors or both are seniors is:
16/36 = 4/9 = 0.444. 
Thus, the answer is choice C.

Five Juniors and Four Seniors Have Applied for Two Open