## Elementary Algebra

To find the percent change, we use the following formula: percent change = $\frac{New\ amount\ -\ Original\ amount}{Original\ amount}$ $\times$ 100% The original blood glucose level was 300 mg/dL. The new blood glucose level is 180 mg/dL. Substituting these values into the formula yields: percent change = $\frac{180-300}{300}$ $\times$ 100% percent change = $\frac{-120}{300}$ $\times$ 100% percent change = -0.4 $\times$ 100% percent change = -40% The patient’s percent decrease in his blood glucose level is 40%.