He works average 35.483... hours per day.
Explanation
Suppose, Larry works average [tex]x[/tex] hours per day.
As he works for 15 days, so the total number of hours he worked [tex]=15x[/tex] hours.
Given that, he works 15 days for a total of 532.25 hours. So the equation will be....
[tex]15x=532.25\\ \\ x=\frac{532.25}{15}=35.483...[/tex]
So, he works average 35.483... hours per day.