Problema Solution
A doctor prescribes an ointment that is 2% hydrocortisone. A pharmacist has 1% and 5% concentrations in stock. How many ounces of each should the pharmacist use to make a 9-ounce tube?
Answer provided by our tutors
let
x = ounces of 1% hydrocortisone ointment
y = ounces of 5% hydrocortisone ointment
we need to make 9-ounce tube thus
x + y = 9
the 9-ounce tube needs to have 2% hydrocortisone
0.01x + 0.05y = 0.02*9
by solving the system of equations
x + y = 9
0.01x + 0.05y = 0.02*9
we find
x = 6.75 oz
y = 2.25 oz
click here to see the step by step solution of the system of equations
we need 6.75 ounces of 1% and 2.25 ounces of 5% hydrocortisone concentration ointment.