Answer:
350 gallons
Step-by-step explanation:
Let x = number of gallons of 70% solution
100 = number of gallons of 25% solution
Then, x + 100 = number of gallons of 60% solution
0.70x + 0.25(100) = 0.60(x + 100)
0.70x + 25 = 0.60x + 60
0.10x = 35
x = 350 gal
Mix 350 gal of 70% solution with 100 gal of 25% solution to obtain 450 gal of 60% solution.
Answer: Add 315 gallons of 70% antifreeze to 90 gallons of 25% antifreeze to make a 60% mixture.
