Stéphanie visited a financial institution and signed a 10-year, non-interest-bearing promissory note for $6000. She intends to give this to her son William, to partly fund his education. Due to...

Stéphanie visited a financial institution and signed a 10-year, non-interest-bearing promissory note for $6000. She intends to give this to her son William, to partly fund his education. Due to unforeseen circumstances, the note is purchased
after only 25 months at 2.15% compounded quarterly.

In order to find the selling price of the note (i.e. the proceeds), which variable is to be calculated?