The volume of the 12% salt solution to be added is; 2.5 gallons.
Let the volume of 12% required be x and the new volume of the mixture be (x+5).
On this note, it follows that;
Hence, -2x = -5
Divide both side by -2;
x = 2.5 gallons.
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Answer:
5
Step-by-step explanation:
I'm pretty sure the answer is D