<PRE><B>Question 153663</B>
A hospital staff mixed 70% disinfectant solution with a 30% disinfectant solution. How many liters of each were used to make a 30L of a 45% disinfectant
:
Let x = amt of 70% disinfectant
:
the resulting amt is to be 30L, therefore:
(30-x) = 30% stuff
:
Write a decimal equation representing this problem
:
.7x + .3(30-x) = .45(30)
:
.7x + 9 - .3x = 13.5
:
.7x - .3x = 13.5 - 9
:
.4x = 4.5
x = {{{4.5/.4}}}
x = 11.25L of 70% stuff required
then
30 - 11.25 = 18.75L of 30%
:
:
Check solution:
.7(11.25) + .3(18.75) = .45(30)
 7.875 + 5.625 = 13.5; confirms our solutions

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