Question

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 95​?

Answer 1

$\bf \begin{array}{ccll} hours&score\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 9&72\\ h&95 \end{array}\implies \cfrac{9}{h}=\cfrac{72}{95}\implies \cfrac{9\cdot 95}{72}=h$