This example models a home mortgage. The user is prompted for the monthly payment, the length of the mortgage, and the interest rate. The model then solves for the value of the home that can be purchased with the mortgage.

MODEL:

! A model of a home mortgage(WHATIF.LNG);

! The user is prompted for values for the

 payment, years, and interest rate. The

 face value of the mortgage (LUMP) is

 solved for.;

DATA:

! User is prompted for these:

  PAYMENT  = ?; ! Monthly payment;

  YEARS    = ?; ! No. of years;

  YRATE    = ?; ! Interest rate;

ENDDATA

 

! Relate no. of months to no. of years;

  MONTHS = YEARS * 12;

 

! Relate monthly interest rate to yearly rate;

  ( 1 + MRATE) ^ 12  =  1 + YRATE;

 

! Relate lump sum to monthly payment, monthly

 interest rate, and no. of months;

  LUMP = PAYMENT * @FPA( MRATE, MONTHS);

 

END

Model: WHATIF