Question:
Solution:
Step 1: Calculate the number of students that touch screen phone in a sample of 816 students:
Let's denote by x the number of students that touch screen phone and consider the following diagram :
By cross-multiplication, solve for x:
![x\text{ = }((816)(18))/(24)=612](https://img.qammunity.org/2023/formulas/mathematics/college/x5zuo08f8i7kdz3p3f7l7o3qt9mray2vz0.png)
Step 2: Subtract the obtained value of step 1 to 816
![816-612\text{ = 204}](https://img.qammunity.org/2023/formulas/mathematics/college/1b9wpsisgzrfrrq1trgljca7970xvtmow9.png)
then, we can conclude that 204 students do not have a touch screen phone.