Using this from what I found helped me answer the question, and if you compare their ratios, they are both going to show that 75% each class have texted:
Proportional: When quantities have the same relative size. In other words they have the same ratio.
All you would have to do is compare the amount of students that texted(x) to the amount of students there are total in the class(y). When you compare them in a y:x format, it will all lead up to the results showing that 75% of both groups have texted.
