Question

as a nurse, part of your daily duties is to mix medications in the proper proportions for your patients. for one of your regular patients, you always mix medication a with medication b in the same proportion. last week, your patients doctor indicated that you should mix 100 milligrams of medication a with 90 milligrams of medication b. however this week, the doctor said to only use 72 milligrams of medication b. set up and solve a proportion to find how many milligrams of medication a should be mixed this week.

Explanation:

Step1: Set up the proportion

Let $x$ be the amount of Medication A. The proportion is $\frac{100}{90}=\frac{x}{72}$ since the ratio of Medication A to Medication B is the same.

Step2: Cross - multiply

$90x = 100\times72$

Step3: Solve for $x$

$x=\frac{100\times72}{90}=\frac{7200}{90}=80$

Answer:

80