Determine the 15" term in the sequence 80, 71, 62, 53, . ... b) Find the common ratio for the geometric sequence 3, 2, + Im c) Find the sum of an arithmetic series where a - -5, d = =, and n = 10 d) Gabe borrows $8000 from a financial institution that charges 5% annual interest, compounded yearly, for 5 years. Find the amount of interest that he will need to pay at the end of the term