Answer:
at 9 : 40
Explanation:
Mr. Still's class has music for 50 minutes and then independent reading for 20 minutes.
50 minutes and then 20 minutes = 50 + 20 = 70 minutes
60 minutes = 1 hour
70 minutes = 1 hour 10 minutes
Music starts at 8:30, so the time after 1 hour 10 minutes it would be
8 : 30
+ 1 : 10
9 : 40
Mr. Still's class finish independent reading at 9 : 40.