An english instructor asserted that students' test grades are directly proportional to the amount of time spent studying. lisa studies 9 hr for a particular test and gets a score of 72. at this rate, how many hours would she have had to study to get a score of 96?

12 hours.

Step-by-step explanation:

1. The direct proportion has the following form:

Where k is the constant of proportionality.

2. Let's call the student's test grade and  the amount of time spent studying , then if Lisa studies 9 hr for a particular test and gets a score of 72, you can find k:

3. Then, the amount of time she have had to study to get a score of 96 is:

what is the answer?