Question

Number of people in a company who drink tea is $45$ while the number of people who drink coffee is $34$ while $12$ people drink both. What is the number of people who only drink either one of tea or coffee?

• A. 65
• B. 55
• C. 45
• D. 35

Answer 1

The correct option is B 55

Let $A\text{and}B$ be the set of people who drink tea and coffee respectively.

To find the number of people who only drink either tea or coffee we will find the symmetric difference of $A\text{and}B.$
$\Rightarrow n\left(A\Delta B\right)=n\left(A\right)+n\left(B\right)-2n(A\cap B)$
$=45+34-2\left(12\right)=55$