A chemical mixture is 40% acid. If you have 500 mL of the mixture, how much pure acid is in it? Then, if you add 100 mL of pure acid, what is the new percentage?
Answer
44.44 percent
How to solve it
1
Pure acid in original: 500 × 0.40 = 200 mL
2
After adding 100 mL acid: 200 + 100 = 300 mL acid
3
New total volume: 500 + 100 = 600 mL
4
New percentage: (300 ÷ 600) × 100 = 50%
Hints
Calculate pure acid in original mixture
Add the pure acid
Divide by new total volume