The values of .

The simple interest formula is where p represents the principal in dollars, r represents the annual interest rate, and t represents the time in years.

Write improper fraction of .

Here months are convert into years as follows.

1 year = 12 months then 1 month = years. \ \

Therefore 18 months = years.

Substitute the values of in the simple interest formula.

Cancel common terms.

dollars.

The simple interest is 1,162.5 dollars.