To find the ratio of the number of students who want lemonade to the total number of students, we can follow these steps:
- Count the number of students who want lemonade: There are 7 students.
- Count the number of students who want iced tea: There are 12 students.
- Calculate the total number of students: Total = students who want lemonade + students who want iced tea = 7 + 12 = 19 students.
- Set up the ratio: The ratio of students who want lemonade to the total number of students is \( \frac{7}{19} \).
Thus, the ratio of the number of students who want lemonade to the total number of students is \( \frac{7}{19} \).