Answer:
The volume of the 50% solution used is 0.8 gallons and the volume of 25% solution used is 1.2 gallons.
Step-by-step explanation:
Let the volume of the 50% solution be be x gallons.
Let the volume of 25% solution be y gallons.
Total volume of the solution after mixing above volumes of the solutions = 2 gallons
x gal + y gal = 2 gal
...[1]
Percentage of the final salt solution = 35%


....[2]
On solving [1] and [2] , we get:
x = 0.8 , y = 1.2
So, the volume of the 50% solution used is 0.8 gallons and the volume of 25% solution used is 1.2 gallons.