A table showing Gallons of Solution, Acid Concentration, and Amount of Acid. The first row shows 10 percent Acid, and has the entries, 0.5, 0.10, and 0.10 times 0.5. The second row shows 35 percent, and has the entries, g, 0.35, and 0.35 g. The third row shows. Mixture, and has the entries, g plus 0.5, 0.15, and 0.15 left parenthesis g plus 0.5 right parenthesis. (0.10)(0.5) + 0.35g = 0.15(g + 0.5)
Eli wants to combine 0.5 gallon of a 10% acid solution with some 35% acid solution to make a 15% acid solution.

How much of the 35% acid solution should Eli add?

gallon