SOLUTION: A hospital staff mixed a 75% disinfectant solution with a 25% disinfectant solution. How many liters of each were used to make 30 L of a 45% disinfectant solution?

Question 798711: A hospital staff mixed a 75% disinfectant solution with a 25% disinfectant solution. How many liters of each were used to make 30 L of a 45% disinfectant solution?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = liters of 75% solution needed
Let = liters of 25% solution needed
--------------
(1)
(2)
-----------------------------
(2)
(2)
(2)
Multiply both sides of (1) by and
subtract (1) from (2)
(2)
(1)

and, since
(1)
(1)
12 liters of 75% solution are needed
18 liters of 25% solution are needed
check:
(2)
(2)
(2)
(2)
(2)

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