Q13 / 35 · NTA Abhyas (JEE Main) 2020 · Mathematics · Sets and Relations

For two sets $A$ and $B$ , if $n (A) = 20, n (B) = 18$ and $n (A \cap B) = 5$ , then $n (A - B)$ is equal to

A
$13$
B
$12$
Correct answer
C
$15$
D
$18$

Solution

n (A - B) = n (A \cup B) - n (B) = n (A) - n (A \cap B)

= 20 - 5

= 15

Hence, the correct answer is option: 'C'.

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