Just doing the math in my head...even subtracting
all of Sat/Sun...subtracting sleep time (I know, that can be very little)...a couple of hours eating/showering...doesn't leave a lot of time for studying...
Of course, we all know 'multi-tasking' is a superior life style (regardless of the scientific fuddy-duddy studies), so they are probably studying a lot of that 7½ hours, also...