Question

This table shows how many sophomores and juniors attended two school events. What is the probability that the student attended the volleyball game, given that the student is a sophomore

A
B
C
or D

Answer 1

Option: B is the correct answer.

B. 0.55

Explanation:

Let A denote the event that the student is a sophomore.

and B denote the event that the student attend the volleyball game.

and A∩B denote the event that the student is a sophomore and attend volleyball game.

Let P denote the probability of an event.

We are asked to find the probability : P(B|A)

We know that:

`P(B|A)=(P(A\bigcap B))/(P(A))`

Based on the table provided to us we have:

`P(A)=(77)/(137)`

and

`P(A\bigcap B)=(42)/(137)`

Hence, we have:

`P(B|A)=((42)/(137))/((77)/(137))`

i.e.

`P(B|A)=(42)/(77)=0.55`

Answer 2

B 0.55

Explanation:

the student is a sophomore - so youre looking at the sophomore row, 77 sophomores total

the student attended the volleyball game - 42 sophomores attended the game

42 / 77 students total = about 0.55