Question

This table shows how many sophomores and juniors attended two school events. A student is selected randomly from this group.

Answer 1

Answer: B. 0.45

Explanation:

From the given table, the total number of students = 137

The number of students are sophomores =35+42=77

Let A be the event that students are sophomores.

Then probability that students are sophomores is given by :

`\text{P(A)}=(77)/(137)`

The number of sophomores who attended the jazz concert = 35

Let B be the event that students attended the jazz concert .

The probability that students attended the jazz concert and are sophomores is given by :

`\text{P(A and B)}=(35)/(137)`

Now, the probability of that the student attended the jazz concert, given that the students is sophomore is given by :-

`P(B|A)=\frac{\text{P(A and B)}}{\text{P(A)}}\\\\=((35)/(137))/((77)/(137))\\\\\\=(35)/(77)=0.454545454545\approx0.45`