If a medication is available as a 20 mg/mL solution, how many mL are needed for a dose of 80 mg?

To determine how many mL are required for a dose of 80 mg from a solution that has a concentration of 20 mg/mL, you can use the formula:

Amount of medication needed (mg) = Concentration (mg/mL) × Volume (mL).

Rearranging this formula to find the volume gives:

Volume (mL) = Amount of medication needed (mg) / Concentration (mg/mL).

Plugging in the values:

Volume (mL) = 80 mg / 20 mg/mL = 4 mL.

This calculation shows that to achieve a dose of 80 mg from a solution that provides 20 mg per mL, 4 mL of the solution is required. Therefore, the answer is correct, as it accurately reflects the relationship between the dose needed and the concentration of the solution.