Ratios & Proportions Practice Test

A lab solution is made by mixing acid and water in the ratio $3:17$ (acid:water). A technician has $255$ mL of water available and wants to keep the ratio exact. How many milliliters of acid should be added?

A class has a ratio of freshmen to sophomores to juniors of $4:5:3$. There are $72$ students in the class total. How many sophomores are in the class?