To determine the proportion of seventh-graders who favor mountains, we first need the number of seventh-graders who prefer mountains and the total number of seventh-graders.
From the table provided:
- Total 7th Grade: 110
- 7th Grade who prefer Seacoast: 70
- 7th Grade who prefer Mountains: \( 110 - 70 = 40 \)
Now that we know there are 40 seventh-graders who prefer mountains, we can calculate the relative frequency (or proportion) of seventh-graders who prefer mountains:
\[ \text{Relative frequency} = \frac{\text{Number of 7th graders who prefer mountains}}{\text{Total number of 7th graders}} = \frac{40}{110} \]
Now we can calculate this fraction:
\[ \frac{40}{110} \approx 0.3636 \]
To express this as a percentage, multiply by 100:
\[ 0.3636 \times 100 \approx 36.36% \]
Rounding to the nearest tenth, we get:
\[ 36.4% \]
So, the answer is:
36.4%