Firefighter Practice Exam

If a solution contains 35% benzene and 65% water, what percentage of benzene is present after adding 4.5 liters of water to 14 liters of the solution?

1. 23.7%

2. 31.7%

3. 26.49%

4. 43.55%

The correct answer is: 31.7%

To determine the percentage of benzene after adding water to the solution, we first need to calculate the initial amounts of benzene and water in the 14 liters of the solution. In the original solution, which contains 35% benzene and 65% water: - The amount of benzene in 14 liters can be calculated as \(0.35 \times 14\) liters, resulting in 4.9 liters of benzene. - The amount of water in 14 liters is \(0.65 \times 14\) liters, which gives us 9.1 liters of water. Next, we add 4.5 liters of water to the existing solution. This increases the amount of water to: - \(9.1 + 4.5 = 13.6\) liters of water. Now, to find the total volume of the new solution, we add the volumes of benzene and water together. The total volume will be: - \(4.9\) liters (benzene) + \(13.6\) liters (water) = \(18.5\) liters (total solution). Finally, to find the percentage of benzene in the new solution, we use the