First period of 14-1=13 weeks = 7×13=91 sessions (1 week's holiday);
Second period of 25-4=21 weeks = 10×21=210 sessions (4 weeks' holiday);
Third period of 13-1=12 weeks = 7×12=84 sessions (1 week's holiday). Total sessions for 14+25+13=52 weeks=385.
(a) Average sessions/week=385/52=7.40, or about 7 sessions/week to the nearest whole number.
(b) Assuming that the subscription rate changes in the first period and then remains at the new rate till the end of the calendar year, the subscription for the first period of 14 weeks is 14/52×3850=£1036.54 followed by 38/52×5295=£3869.42. Total subscription: £4905.96 for the year.
However, it's more likely that the old subscription rate would apply for 13 weeks (first quarter) in the first period and 39 weeks (last three quarters) making the amount=£962.50+£3971.25=£4933.75 for the year. Note that this cost does not involve the number of sessions, whereas the answer to part (a) only involves the number of sessions.
[It's not clear whether the question is asking for the subscription costs in relation to the average number of sessions. Average cost per session would then be 4933.75/385=£12.81 to the nearest penny. This is 4905.96/385=£12.74 if we use the first figure for the total subscription, based on the first period of 14 weeks, instead of 13, and the second and third periods totalling 38 instead of 39 weeks. Furthermore, if we take the rounded 7 sessions per week then 7×52=364 sessions instead of 385. Then the two figures for average subscription cost per session become £13.48 and £13.55 instead of £12.74 and £12.81.]