## Elementary Algebra

To find the interest charged, we use the interest formula. The interest formula is: I = P $\times$ r $\times$ t P = 8000 r = 8.5% = 0.085 t = 9 months = 9 $\times$ $\frac{1}{12}$ = 0.75 (Because 1 month = $\frac{1}{12}$ year.) Substitute these values in the formula to obtain: I = 8000 $\times$ 0.085 $\times$ 0.75 I = 510 The interest charged will be 510 dollars.