## Elementary Algebra

To find the percent change, we use the following formula: percent change = $\frac{New\ amount\ -\ Original\ amount}{Original\ amount}$ $\times$ 100% The bill in July was 120. The bill in August was 140. Substituting these values into the formula yields: percent change = $\frac{140-120}{120}$ $\times$ 100% percent change= $\frac{20}{120}$ $\times$ 100% percent change = 0.166666 $\times$ 100% $\approx$ 0.1667 $\times$ 100% percent change = 16.67% $\approx$ 17% The percent decrease in the electric utility bill from July to August was 16.67%, or approximately 17%.