Answer
The percent of change in the patient’s dosage is -25%.
The dosage amount decreased by 25%.
Work Step by Step
To find the percentage change, we use the following formula:
percentage change = $\frac{New\ amount\ -\ Original\ amount}{Original\ amount}$ $\times$ 100%
The original dosage was 40 milligrams. The new dosage is 30 milligrams. We substitute these values into the formula to obtain:
percentage change = $\frac{30\ -\ 40}{40}$ $\times$ 100%
percentage change = $\frac{-10}{40}$ $\times$ 100%
percentage change = -0.25 $\times$ 100%
percentage change = -25%
Because it is a negative number, it is a percent decrease.
