Question

Two solutions of salt water contain 0.07% and 0.27% salt respectively. A lab technician wants to make 1 liter of solution which contains 0.16% salt. How much of each solution should she use?

Answer 1

• 0.45 L of 0.27%
• 0.55 L of 0.07%

Explanation:

Let x represent the number of liters of 0.27% solution she should use. Then the amount of salt in the mixture is ...

0.27x +0.07(1 -x) = 0.16(1) . . . . . all percentages multiplied by 100

0.20x = 0.09 . . . . . . . subtract 0.07 and simplify

x = 0.09/0.20 = 0.45 . . . . . divide by 0.20

She should use 0.45 liters of 0.27% solution and 0.55 liters of 0.07% solution.