we have the following:
The first time in hours, normally, like this
[tex]\begin{gathered} 7\colon15AM\rightarrow12\colon45PM=5\colon30h \\ 1\colon45PM\rightarrow6\colon00PM=4\colon15h \end{gathered}[/tex]now, we calculate the total time:
[tex]5\colon30h+4\colon15h=9\colon45h[/tex]now we convert it to decimal form, knowing that 45 minutes is 3/4 of an hour, that is 0.75, therefore, the answer is:
[tex]9.75h[/tex]