What is the length of BC, AC, ED, DK, &’ EK? sorry there’s so many!! it’s at 15 points!

Afitness center has 2 membership plans one has a low dollar sign up fee of 15 dollars and costs 38 dollars per month to join. a second plan has a higher sign up fee of 78 dollars but a lower monthly fee of 31 dollars for what number of days of the month is the coat the same