Question

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 5-ounce tube?.

Answer 1

`1.25` ounes of
`1`% and
`3.75` ounes of
`5`% will be used to make a
`5`-ounce tube

Step-by-step explanation:

let "x" represent the number of ounces of
`1`% concentration

Then the number of ounces of
`5`%concentration would be
`5-x`

Now the total of ounces of
`1`% and
`5`% would be equal to
`5`-ounce of
`4`% hydrocortisone.

so the equation will be

`0.01 (x) + 0.05(5-x) = 0.04*5\\0.01x-0.05x+0.25= 0.2\\\\0.25-0.2= 0.04x\\x = (0.05)/(0.04) \\x= 1.25\\5-x= 5-1.25 = 3.75`

hence

`1.25` ounes of
`1`% and
`3.75` ounes of
`5`% will be used to make a
`5`-ounce tube