How many tablets should a 39 kg patient take every four hours?

50 mg/kg/day x 34 kg = 1700 mg/day

1700 mg/day x 1 day/24 hrs x 4 hrs = 283 mg every 4 hrs

283 mg/4hrs x 1 tablet/400 mg = 0.7 tablets

So to acieve the desired dose, the pati should take seven tenths of a tablet every 4 hours. Thats an unusual dosage since it's difficult to take 0.7 tablet. The question didnt ask about the liquid suspension so I didn't include that.