Problema Solution
A doctor prescribes an ointment that is 4% hydrocortisone. A pharmacist has 1% and 5% concentrations in stock. How many ounces of each should the pharmacist use to make a 1-ounce tube?
Answer provided by our tutors
let 'x' represent the amount of 1% ointment used, then '1-x' represents the amount of 5% ointment used
0.04(1.) = 0.01x + 0.05(1-x)
solving for 'x' we have x=0.25
1-0.25 = 0.75
the pharmacist should use 0.25 ounces of 1% ointment mixed with 0.75 ounces of 5% ointment