Ratios, Proportions, and Absolute Value Practice Test

In a dental clinic, the ratio of disposable gloves used by the hygienists to those used by the dentists is $$5:3$$. If the clinic ordered 640 pairs of gloves for hygienists this month, how many pairs were ordered for dentists, assuming the same ratio is maintained?

A laboratory needs to prepare a buffer solution where the ratio of acid to base to salt is 1:3:2. If the final solution must contain exactly 240 mL of base, and the absolute deviation of the acid concentration from 16.67% must not exceed 0.83%, what is the range of possible total volumes for the solution?