Question

In a classroom of 20 students, 70% of them have brown eyes. If a teacher picks two students

at random to pass out supplies, what is the probability he chooses two students without brown
eyes?
49
A)
100
B)
91
190
3
C)
38
9
D)
100

Answer 1

The probability is 9/100

Explanation:

First, we know that 70% of the students are with brown eyes. Since we have a total of 20 students, this corresponds to 70/100 * 20 = 14 students

The number of students without brown eyes is thus 20 -14 = 6 students

Now, the probability of selecting a student without brown eyes is 14/20 = 7/10 while the probability of selecting a student with brown eyes is 6/20 = 3/10

Now the probability of selecting two students without brown eyes mean, the first selected is without brown eyes and also the second selected is without brown eyes.

In probability, once we have the work and, we multiply.

So our answer here is 3/10 * 3/10 = 9/100