Based on a rate of 3% per quarterly period. With which equal payments at the end of 2 years and at the end of 5 years, it is possible to replace the following obligations: s /. 12 000.00 with maturity in 4 years and interest at 6% capitalizable on a six-monthly basis, s /. 18 000.00 with interest at 2.5% per month due in 7 years?