We know that Joe practiced from 6:30 to 7:05 An hour is 60 minutes Joe practiced for the 30 minutes left in that hour and 5 minutes into the next
30+5=35
So, he was playing for 35 minutes on the first day
Now, we can do the same thing for the second day:
He started at 3:55 and ended at 4:15 An hour is 60 minutes <span>Joe practiced for the 5 minutes left in the hour and the first 15 minutes of the next hour </span> 5+15=20
Now we want to add the number of minutes he practiced for both days