SOLUTION: a nurse needs rubbing alcohol, which is a 70% alcohol solution. However, there is only a 40% alcohol solution and a 90% alcohol solution in stock. how much of each solution should

Question 1093599: a nurse needs rubbing alcohol, which is a 70% alcohol solution. However, there is only a 40% alcohol solution and a 90% alcohol solution in stock. how much of each solution should be mixed in order to obtain 8 ounces of the desired solution?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = ounces of 40% solution needed
Let = ounces of 90% solution needed
-------------------------------------------
(1)
(2)
----------------------------
(2)
(2)
Multiply both sides of (1) by
and subtract (1) from (2)
-----------------------------------
(2)
(1)
--------------------------

and
(1)
(1)
(1)
-----------------------
3.2 ounces of 40% solutions are needed
4.8 ounces of 90% solution are needed
-------------------------------------
check:
(2)
(2)
(2)
(2)
OK
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