A burette pump is set to administer 80 mL of fluid containing 80 mg of gentamicin in 45 minutes. What is the rate in mL/h?

A burette pump is set to administer 80 mL of fluid containing 80 mg of gentamicin in 45 minutes. What is the rate in mL/h?

• A. 105 mL/h
• B. 106 mL/h
• C. 107 mL/h
• D. 108 mL/h

Answer: (C)

Rate is volume delivered per unit time. Here, 80 mL is delivered in 45 minutes. Convert time to hours: 45 minutes = 0.75 hours. Then the rate is 80 mL / 0.75 h = 106.666... mL/h, which rounds to 107 mL/h. Since the solution concentration is 1 mg/mL (80 mg in 80 mL), the corresponding drug amount would be about 106.7 mg/h if you needed mg per hour, but the asked unit is mL/h, so the key idea is converting the time to hours and dividing the volume by that time.

Rate is volume delivered per unit time. Here, 80 mL is delivered in 45 minutes. Convert time to hours: 45 minutes = 0.75 hours. Then the rate is 80 mL / 0.75 h = 106.666... mL/h, which rounds to 107 mL/h. Since the solution concentration is 1 mg/mL (80 mg in 80 mL), the corresponding drug amount would be about 106.7 mg/h if you needed mg per hour, but the asked unit is mL/h, so the key idea is converting the time to hours and dividing the volume by that time.