One type of liquid contains 25 % of benzene, the other contains 30% of benzene. A can is filled with 6 parts of the first liquid and 4 parts of the second liquid. Find the percentage of benzene in the new mixture.

We are given two types of liquids:

• First Liquid: Contains 25% benzene.
• Second Liquid: Contains 30% benzene.

The mixture is formed by combining:

• 6 parts of the first liquid
• 4 parts of the second liquid

Step 1: Understand the Goal
We are to find the overall percentage of benzene in the final mixture created by mixing these two liquids in the given ratio.

Step 2: Use Weighted Average Formula

The formula for the percentage of benzene in the mixture is:

Percentage of Benzene = 
  [(Part₁ × %₁) + (Part₂ × %₂)] / (Part₁ + Part₂)

Substituting the values:

Percentage of Benzene = 
  [(6 × 25) + (4 × 30)] / (6 + 4)
= (150 + 120) / 10
= 270 / 10
= 27%

Step 3: Final Answer

The final mixture contains 27% benzene.

✅ Correct Option: B. 27%

This method is based on the concept of weighted averages, where the influence of each percentage depends on how much of each component is used in the total mixture. Since more parts of the first liquid (25% benzene) are used compared to the second, the resulting percentage lies closer to 25% than 30%.