Need finding out the recursive formula? ! really stuck on this problem.

Given that anna wants to spend less than $60 for the subscription and only full month subscriptions are offered, what is the maximum number of months that ana can subscribe

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is

Given the graphed function below which of the following orders pairs are found on the inverse function