need your help.. please answer this question.

finding the outstanding principal
1. Mang tomas a farmer had an obligation to Land bank of the Philippines to be amortized by quarterly payments of P1,670 for 5 years. IF the interest is at 6% compounded quarterly, find:
a. Present value of the loan
b.the outstanding principal after 4 years
c. The remaining liability just after 18th payment
d. how much of the 20th payment is interest and how much goes to principal


2. Ms. rina had a debt of P56,000 to their community credit union, with the interest at 5% compounded monthly, will be discharged, interest included, by monthly payments of P1,500 for as long as necessary. find:
a. numbers of regular payments/total conversion(n)
b. the outstanding principal after two years and six months
c. final or concluding payment.