To determine the percentage of the people surveyed who cannot swim, we need to follow a structured approach, focusing on the given relative frequencies:
1. Identify the given relative frequencies:
- For adults who cannot swim: 0.06
- For children who cannot swim: 0.12
2. Calculate the total relative frequency of people who cannot swim:
- Sum the relative frequencies of adults and children who cannot swim:
[tex]\[
\text{Total relative frequency} = 0.06 + 0.12 = 0.18
\][/tex]
3. Convert the total relative frequency to a percentage:
- We know that:
[tex]\[
\text{Percentage} = \text{Relative frequency} \times 100
\][/tex]
- Substitute the total relative frequency:
[tex]\[
0.18 \times 100 = 18.0
\][/tex]
4. Identify the correct answer:
- The calculated percentage of people who cannot swim is 18%.
Thus, the percentage of people surveyed who cannot swim is:
[tex]\[
\boxed{18\%}
\][/tex]
This matches option C.
