What is the percent concentration of benzene in a solution containing 59 mL of benzene and 150 mL toluene?

A 28.2%

explanation

In order to get this answer, we need to first divide the volume of benzene (59 mL) by the total volume of the solution ( 59 + 150 = 209 mL).
59 ÷ 209 = 0.282
We then multiply by 100 to convert the decimal in a percent.
0.282 × 100 = 28.2%.