Mark borrowed an amount of P8430 from Brian and after 2 years, he borrowed again an amount of P2650. He paid P3300 one year after last borrow, P2800 the following year, and P1100 a year after. If the money is worth 8.45% compounded quarterly.

Determine the following:

a.) amount he should pay 7 years after the last borrow to discharge all his debts.

b.) Amount he should pay as a single lump sum at the end of 6th year to discharge all his debts.