A mixture problem: 2 parts A at 20% and 3 parts B at 60% yield what overall percentage?

• A. 40%
• B. 44%
• C. 50%
• D. 48%

Answer: (B)

When mixing amounts with different concentrations, the overall percentage is found by a weighted average: add up the actual amount of solute contributed by each part and divide by the total amount of mixture.

Here, two parts are at 20% and three parts at 60%. Solute from the first part is 2 × 0.20 = 0.40. Solute from the second part is 3 × 0.60 = 1.80. Total solute = 0.40 + 1.80 = 2.20. Total parts = 2 + 3 = 5. Overall percentage = 2.20 / 5 = 0.44, or 44%.

This result lies between 20% and 60%, and accounts for the greater share from the 60% portion, so 44% is the correct overall percentage.