If the patient has to get 1.5 gram of the antibiotic in 3 equal doses,
in each dose, he has to take = 1.5/3 = 0.5 gram
0.5 gram = 0.5×1000 milligram = 500 milligram
amount of antibiotic in 1 tablet = 250 mg
for 500mg, no. of tablets = 500/250 = 2
So the patient should take 2 tablets in each dose.