SOLUTION: A pharmacist wants to make 18 ml of a 6% hydrogen peroxide solution. How many mls of 5% hydrogen peroxide must he mix with 7% hydrogen peroxide to make the desired solution?

Question 596472: A pharmacist wants to make 18 ml of a 6% hydrogen peroxide solution. How many mls of 5% hydrogen peroxide must he mix with 7% hydrogen peroxide to make the desired solution?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = ml of 5% solution needed
Let = ml of 7% solution needed
= ml of hydrogen peroxide in 5% solution
= ml of hydrogen peroxide in 7% solution
----------------------------------------
given:
(1)
(2)
--------------------------
(2)
(2)
(2)
Multiply both sides of (1) by and
subtract (1) from (2)
(2)
(1)

and, since
(1)
(1)
(1)
9 ml of 5% solution is needed
9 ml of 7% solution is needed
check:
(2)
(2)
(2)
(2)
(2)
(2)
OK
RELATED QUESTIONS
a pharmacist wants to make 40 ml of a 76% hydrogen peroxide solution how many mls of 55%... (answered by josmiceli)

How many milliliters of a 18% hydrogen peroxide solution and how many milliliters of a... (answered by josgarithmetic)

How many milliliters of a 25% hydrogen peroxide solution and how many milliliters of a 9% (answered by lwsshak3)

How many pints of 1% hydrogen peroxide peroxide solution should be mixed with 4% hydrogen (answered by addingup)

want to make 12 liters of a 40% hydrogen peroxide solution consisting of a combo of 70% (answered by checkley79)

A hair dye is made by blending a 7% hydrogen peroxide solution and a 4% hydrogen peroxide (answered by ptaylor)

I am stuck on this math word problem. It states: you need to make a 600mL solution of... (answered by KMST)

how many milliliters of a 10% hydrogen peroxide solution and how many milliliters of a 2% (answered by stanbon,Alan3354)

A cosmetologist has a bottle of 7% hydrogen peroxide solution and a bottle of 4% hydrogen (answered by richwmiller)