How many pints of a 7% cleaning solution must be mixed with 9 pints of a 15% cleaning solution to give a 13% solution?
A) 6 pints
B) 3 pints
C) 4 pints
D) 9 pints

Question

Quizplus · Accepted Answer

To solve this, we use the equation for mixture problems: (amount of first solution * its percentage + amount of second solution * its percentage) / total amount of solution = desired percentage. Let x be the amount of the 7% solution. The equation is: (0.07x + 0.15*9) / (x + 9) = 0.13. Solving for x gives 3 pints.

How Many Pints of a 7% Cleaning Solution Must Be