To determine the percentage of people surveyed who cannot swim, let's examine the given relative frequency table. The table provides relative frequencies for adults and children who can swim and cannot swim.
First, let's identify the relevant relative frequencies:
- The relative frequency of adults who cannot swim: 0.06
- The relative frequency of children who cannot swim: 0.12
Next, we need to calculate the total relative frequency of people who cannot swim by adding the individual relative frequencies for adults and children:
[tex]\[ \text{Total relative frequency of people who cannot swim} = 0.06 + 0.12 = 0.18 \][/tex]
Relative frequency is typically expressed as a fraction of the total population. To convert this relative frequency into a percentage, multiply it by 100:
[tex]\[ \text{Percentage of people who cannot swim} = 0.18 \times 100 = 18\% \][/tex]
Therefore, the percentage of the people surveyed who cannot swim is:
[tex]\[ \boxed{18\%} \][/tex]
Which corresponds to option B.
