To find the number of residents surveyed, we start with the information given in the problem.
Two-fifths of the respondents like spending their vacation at the beach, and this amount is equal to 80 residents. We can express this relationship with the equation:
\[ \frac{2}{5} r = 80 \]
Where \( r \) is the total number of residents surveyed.
To solve for \( r \), we can rearrange the equation:
- Multiply both sides by \( \frac{5}{2} \) to isolate \( r \): \[ r = 80 \times \frac{5}{2} \]
- Calculate that: \[ r = 80 \times 2.5 = 200 \]
Therefore, the equation representing the number of residents surveyed is:
\[ \frac{2}{5} r = 80 \]
And the total number of residents surveyed is:
200 residents.
So, the correct response is:
2/5 r=80; 200 residents were surveyed.