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 patient's doctor indicated that you should mix 70 milligrams of medication a with 21 milligrams of medication b. however this week, the doctor said to only use 9 milligrams of medication b. how many milligrams of medication a should be mixed this week?

Answer 1

To maintain the ratio, for 9 milligrams of medication B, one would mix 70 milligrams of medication A, as the original ratio was 70 milligrams of A to 21 milligrams of B, which simplifies to 10:3.

Step-by-step explanation:

To determine how many milligrams of medication A should be mixed with 9 milligrams of medication B this week, we need to maintain the same ratio of medication A to medication B that was used last week.

Last week, the ratio was 70 milligrams of medication A to 21 milligrams of medication B, which simplifies to a ratio of 10:3.

This week, with only 9 milligrams of medication B, we need to adjust the amount of medication A accordingly. Since 9 is 3 times 3, we divide the original amount of medication A (70 milligrams) by the original ratio number for medication B (3), and multiply by the new amount of medication B:
(70 mg of A / 3) × 9 mg of B = 210 mg of A / 3

= 70 mg of A.

The calculated dose of medication A that should be mixed with 9 milligrams of medication B is then 70 milligrams.