High School

Select the correct answer.

A restaurant has a total of 60 tables. Of those tables, 38 are round, and 13 are located by the window. There are 6 round tables by the window.

If tables are randomly assigned to customers, what is the probability that a customer will be seated at a round table or by the window?

A. [tex]\frac{47}{60}[/tex]
B. [tex]\frac{45}{60}[/tex]
C. [tex]\frac{41}{60}[/tex]
D. [tex]\frac{29}{60}[/tex]

Answer :

First, note that out of 60 tables, there are 38 round tables and 13 tables by the window. However, 6 tables are both round and by the window. To avoid counting these tables twice, we use the inclusion-exclusion principle.

The number of tables that are either round or by the window is given by:
[tex]$$
\text{Union} = (\text{round tables}) + (\text{window tables}) - (\text{round tables by the window})
$$[/tex]
Substitute the given numbers:
[tex]$$
\text{Union} = 38 + 13 - 6 = 45
$$[/tex]

Thus, there are 45 tables that are either round or by the window.

The probability that a customer will be seated at one of these tables is:
[tex]$$
\text{Probability} = \frac{\text{Union}}{\text{Total tables}} = \frac{45}{60} = 0.75
$$[/tex]

Expressed as a fraction, the answer is [tex]$\frac{45}{60}$[/tex], which corresponds to option B.