Question

Among 35 students in a class, 20 of them earned A's on the midterm exam, 13 earned A's on the nal exam, and 12 did not earn A's on either examination. What is the probability that a random

Answer 1

The correct answer is "
`(2)/(7)`".

Explanation:

According to the question,

Number of students,

= 35

A ! mid term A,

`n(A) = 20`

B : final A,

`n(B) = 13`

Didn't start,

`n(A^c \cap B^c) = 12`

Now,

⇒
`n(A \cup B)=35-12`

`=23`

then,

⇒
`n(A \cup B)=20+13-23`

`=10`

hence,

The probability will be:

⇒
`P(A \cap B)=(10)/(35)`

⇒
`=(2)/(7)`