If the medication concentration is 15 mg per mL and you need 60 mg, how many milliliters are required?

If the medication concentration is 15 mg per mL and you need 60 mg, how many milliliters are required?

• A. 2 mL
• B. 6 mL
• C. 1 mL
• D. 4 mL

Answer: (D)

Dividing the desired dose by the concentration converts dose to volume. Since the solution is 15 mg per mL, each milliliter contains 15 mg. To get 60 mg, compute 60 ÷ 15 = 4. The mg units cancel out, leaving milliliters, so you need 4 mL. You can verify by multiplying back: 4 mL × 15 mg/mL = 60 mg, which matches the required dose. For context, a smaller volume would give less than 60 mg (2 mL would be 30 mg, 1 mL would be 15 mg), while a larger volume would give more (6 mL would be 90 mg), so 4 mL is the correct amount.

Dividing the desired dose by the concentration converts dose to volume. Since the solution is 15 mg per mL, each milliliter contains 15 mg. To get 60 mg, compute 60 ÷ 15 = 4. The mg units cancel out, leaving milliliters, so you need 4 mL. You can verify by multiplying back: 4 mL × 15 mg/mL = 60 mg, which matches the required dose. For context, a smaller volume would give less than 60 mg (2 mL would be 30 mg, 1 mL would be 15 mg), while a larger volume would give more (6 mL would be 90 mg), so 4 mL is the correct amount.