In order to cure an aggressive infection, a doctor is giving her patient an initial dose of 325mg of penicillin and a follow up dose of 125mg every two hours after.

Question

If it took her 9 hours to cure the infection, how many mg of penicillin were used?

A)325

B)625

C)825

D)950

Answer 1

325 + 125 (8/2) = 325 + 500 = 825

You use 8 instead of 9 because the patient would get the dosage at hour 8 and 10, not 9. You divide 8 by 2 because it is every 2 hours.