Answer:
The chemist needs 50 mL of 51% solution and 70 mL of 87% solution.
Step-by-step explanation:
If x is the volume of 51% solution, and y is the volume of 87% solution, then:
x + y = 120
0.51x + 0.87y = 0.72(120)
Solve the system of equations.
0.51x + 0.87(120 − x) = 0.72(120)
0.51x + 104.4 − 0.87x = 86.4
0.36x = 18
x = 50
y = 70
The chemist needs 50 mL of 51% solution and 70 mL of 87% solution.
