The prescription says 0.4mg each time, which means taking 2 tablets each time.

Three times a day, so you must take six tablets a day.

15 days is a course of treatment, 15*6=90, so you should take 90 tablets in a course of treatment.

There are 350 tablets in a bottle of medicine, and 350 divided by 90 equals 3 to 80, so a bottle of medicine can take three courses of treatment, and there are 80 tablets left.