Question 1126215
"Mixture", is good.  (But "solution" would not be good.)
These could be dry physical mixes.


---
How many cups of a 
15
%
salt mixture and a 
55
%
salt mixture should you mix to get 
4
cups of a 
45
%
salt mixture?
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x of the 55% mixture
4-x of the 15% mixture

{{{15(4-x)+55x=45*4}}}

-

{{{55x+60-15x=180}}}
{{{40x=180-60}}}
{{{40x=120}}}
{{{highlight(x=3)}}}--------- 3 cups of the 55%
-
{{{highlight(1)}}}---------------------- cup of the 15%