With #90, and with needing 6.5 tablets weekly, we simply divide 6.5 into 90 to find out how many weeks worth of medication this is. Then once you have the quotient, you can multiply the quotient by 7 to get the days supply that it will last.
6.5 into 90 = 13.84615
13.84615 X 7 = 96.923
Round down to get a whole day and your answer is 96 days.
#90 pills, with a sig: Take 1/2 tablet on Mondays, and Take 1 tablet daily on the other days, would last for 96 days.
The other way to look at this question is to interpret your sig as written: Take 0.5 tablet daily on Mondays and Take 1 tablet every other day, meaning QOD (every other day) such that you start with a half tablet on day one, and then on 1 whole tablet the next day, then zero tablets the next day, then a 1 whole tablet the next day...and on and on.
But for the sake of simplicity, I'm going to assume that instead of saying "...and 1 tablet every other day." to mean "and take 1 tablet daily thereafter".
Patient is prescribed 10g of Glucose. The glucose is presented as a 5% solution in 500ml Saline. How much of the 5% dextrose saline solution do you need