## Elementary Algebra

The bill for the month of July was 80.00 dollars. This was 16.00 more than the bill for the month of June, which means that the bill for the month of June was 80.00 - 16.00 = 64.00 dollars. To find the percent change, we use the following formula: percent change = $\frac{New\ amount\ -\ Original\ amount}{Original\ amount}$ $\times$ 100% The previous bill was 64.00 dollars while the new bill was 80.00 dollars. Substituting these values into the formula yields: percent change = $\frac{80.00\ -\ 64.00}{64.00}$ $\times$ 100% percent change = $\frac{16.00}{64.00}$ $\times$ 100% percent change = 0.25 $\times$ 100% percent change = 25% Because the percent change is a positive number, it is a percent increase.