A chemist mixes 20 liters of a 30% acid solution with 30 liters of a 50% acid solution. What is the acid percentage of the resulting mixture?
Answer and explanation
Correct answer: B. 42%
- Step 1: Calculate the volume of pure acid in the first solution: 20 * 0.30 = 6 liters.
- Step 2: Calculate the volume of pure acid in the second solution: 30 * 0.50 = 15 liters.
- Step 3: Find total acid and total liquid: Total acid = 6 + 15 = 21 liters; Total volume = 20 + 30 = 50 liters.
- Step 4: Compute percentage: (21 / 50) * 100% = 42%.
Answer
42%.
Why not the others: Option 40% takes the simple arithmetic average of 30% and 50%, ignoring the unequal volumes. Option 45% weights the second solution excessively. Option 38% miscalculates total acid volume.
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