8) In order the number of weeks are:
6 weeks at 2 sessions/week=12 sessions,
19 weeks at 6 sessions/week=114 sessions,
22 weeks at 10 sessions/week=220 sessions,
5 weeks at 6 sessions/week=30 sessions.
Total sessions=376 in the year (6+19+22+5=52 weeks). Average 376/52=7.23 sessions/week.
In whole numbers this average is 7 sessions per week.
8b) 1st period 2 weeks fewer, 4 sessions fewer;
3rd period 2 weeks fewer, 20 sessions fewer. Total fewer: 24 sessions, 376-24=352 sessions, 352/52=6.77 sessions/week on average.
In whole numbers this average is (still) 7 sessions per week. (The actual difference is less than 0.5 session.)