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

Answer:

The correct answer is "$\frac{2}{7}$".

Step-by-step 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:

⇒ $P(A \cap B)=\frac{10}{35}$

⇒                 $=\frac{2}{7}$