Liliana wants to start a seventh-grade computer club at Hamden Middle School. She surveyed 20 seventh-grade students at the town park. She asked each student how many hours they spend on their computers each week. She obtained the following results:

[tex]\[8, 15, 0, 11, 12, 13, 16, 13, 0, 4, 17, 14, 30, 13, 5, 12, 1, 13, 12, 21\][/tex]

What is the ratio of the total number of students who used their computers to the total number of students surveyed?

A. [tex]$\frac{2}{20}$[/tex] or [tex]$\frac{1}{10}$[/tex]

B. [tex]$\frac{2}{18}$[/tex] or [tex]$\frac{1}{9}$[/tex]

C. [tex]$\frac{18}{20}$[/tex] or [tex]$\frac{9}{10}$[/tex]

D. [tex]$\frac{18}{2}$[/tex] or [tex]$\frac{9}{1}$[/tex]

First, we note that there are 20 students surveyed, so the total number of students is

[tex]$$\text{Total students} = 20.$$[/tex]

Next, we look at the hours each student spends on their computers. A student is considered to have used a computer if the number of hours is more than 0. By inspecting the data, we see that two of the values are 0, meaning those two students did not use their computers. Therefore, the number of students who used their computers is

[tex]$$\text{Students who used computers} = 20 - 2 = 18.$$[/tex]

Now, the ratio of the number of students who used their computers to the total number of students is

[tex]$$\frac{18}{20}.$$[/tex]

Finally, we simplify the fraction by noticing that both the numerator and the denominator are divisible by 2:

[tex]$$\frac{18 \div 2}{20 \div 2} = \frac{9}{10}.$$[/tex]

Thus, the ratio of the students who used their computers to the total number surveyed is

[tex]$$\frac{18}{20} \text{ or } \frac{9}{10}.$$[/tex]