Answer:
The scientist needs 80 liters of 25% solution and 40 liters of 10% solution.
Step-by-step explanation:
If x is the liters of 25% solution, and y is the liters of 10% solution, then:
x + y = 120
0.25x + 0.10y = 0.20(120)
Solve the system of equations using substitution or elimination. Using substitution:
0.25x + 0.10(120 − x) = 0.20(120)
0.25x + 12 − 0.10x = 24
0.15x = 12
x = 80
y = 40
The scientist needs 80 liters of 25% solution and 40 liters of 10% solution.
