Step-by-step explanation:
If x is the volume of 75% solution, and y is the volume of 25% solution, then:
x + y = 500
0.75x + 0.25y = 0.60(500)
Solving the system of equations:
0.75x + 0.25(500 − x) = 0.60(500)
0.75x + 125 − 0.25x = 300
0.50x = 175
x = 350
y = 150
You need 350 mL of 75% solution and 150 mL of 25% solution.
