A debt of P 15,000 was paid for as follows: P 4,000 at the end of 3 months, P 5,000 at the end of 12 months, P 3,000 at the end of 15 months, and a final payment F at the end of 21 months. If the rate...

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Extracted text: A debt of P 15,000 was paid for as follows: P 4,000 at the end of 3 months, P 5,000 at the end of 12 months, P 3,000 at the end of 15 months, and a final payment F at the end of 21 months. If the rate of interest was 18% compounded quarterly, find the final payment F.