What quantity of a 50% acid solution must be mixed with a 20% solution to produce 300 mL of a 40% solution?
A) 100 mL
B) 180 mL
C) 120 mL
D) 240 mL
E) 200 mL

Question

Quizplus · Accepted Answer

To solve this, we can use the equation for mixture problems: (amount of first solution * its concentration) + (amount of second solution * its concentration) = (total amount of mixture * desired concentration). Let x be the amount of the 50% solution, so 300 - x is the amount of the 20% solution. The equation becomes: 0.5x + 0.2(300 - x) = 0.4(300). Solving for x gives x = 200 mL.

What Quantity of a 50% Acid Solution Must Be Mixed