Pharmacy Technician Certification Board (PTCB) Math Practice Exam

To determine how many grams of drug are needed to make a 250 ml solution with a ratio of 2:15, we first need to understand what this ratio means. A 2:15 solution indicates that for every 2 parts of the drug, there are 15 parts of the total solution. This translates to a total of 17 parts (2 parts of drug + 15 parts of solvent).

Next, we can set up a proportion to find out how much of the drug is required for 250 ml. The total volume of the solution can be divided into parts based on the ratio:

1. Calculate the total number of parts in the solution:

2 (drug) + 15 (solvent) = 17 parts.

2. Each part of the solution is then the total volume divided by the number of parts:

Volume of each part = 250 ml / 17 parts ≈ 14.71 ml per part.

3. To find the volume of the drug in the total solution, multiply the number of drug parts by the volume of each part:

Volume of drug = 2 parts × 14.71 ml/part ≈ 29.42 ml.

4. To convert this