$15-$ Tom will pay $10000$ dollars to Monica $2$ years from now. John wants to buy this debt from Monica. How much would John pay to Monica in order to buy this debt if the yearly interest rate in the market is $\backslash (10\backslash \%\backslash )$ for the first year and $\backslash (12\backslash \%\backslash )$ for the following year? $16-$ Alison will receive $1000$ dollars from Jeff in $1$ year and $3000$ dollars in $3$ years. Martin wants to buy this payment from Alison. How much would Martin pay to Alison in order to buy this payment if the yearly interest rate in the market is expected to be $\backslash (5\backslash \%,7\backslash \%\backslash )$ and $\backslash (8\backslash \%\backslash )$ for the next $3$ years?