Answer:
120 mL
Step-by-step explanation:
The amount of acid in the mixture will be the sum of the amounts in the components.
Setup
Let v represent the volume in mL of 5% acid that must be added to make the desired mixture. Then the total volume of acid is ...
0.05v +0.20(60) = 0.10(v +60)
Solution
Simplifying the equation gives ...
0.05v +12 = 0.10v +6
6 = 0.05v . . . . . . . . . . . . subtract 0.05v +6
120 = v . . . . . . . . . . . . divide by 0.05
120 mL of 5% acid must be added.
