To find the joint relative frequency of being an adult who prefers watermelon, we need to follow a few steps:
1. Identify the number of adults who prefer watermelon:
From the table, we see that there are 111 adults who prefer watermelon.
2. Identify the total number of survey respondents:
The total number of respondents, combining children and adults, is given as 445.
3. Calculate the joint relative frequency:
The joint relative frequency is calculated by taking the number of adults who prefer watermelon and dividing it by the total number of survey respondents. This gives us the proportion of the overall respondents who are adults preferring watermelon.
4. Perform the division:
Therefore, we divide the number of adults who prefer watermelon (111) by the total number of survey respondents (445).
[tex]\[
\text{Joint Relative Frequency} = \frac{111}{445} \approx 0.2494
\][/tex]
Hence, the correct choice is:
B. Divide 111 by 445.
This gives us the joint relative frequency of being an adult who prefers watermelon, which is approximately 0.2494 or 24.94%.