You Have Five Hours Left to Study for Two Exams

You have five hours left to study for two exams tomorrow.The relationship between hours of study and test scores is as follows:
$\begin{array}{cccc}& \text { Economics } &&&& { \text { Sociology } } \\ \underline { \text { Hours }}&& \underline { \text { Scare } } &\quad\quad& \underline { \text { Hours }}&& \underline { \text { Scare } } \\1 && 50 &\quad\quad\quad& 1 && 75 \\2 && 65 &\quad\quad& 2 && 85 \\3 && 75 &\quad\quad& 3 && 90 \\4 && 80 &\quad\quad& 4 && 93 \\5 && 85 &\quad\quad& 5 && 5\end{array}$
Use the rule for determining optimal purchases to allocate your time, where each point is one "util" of utility.