Question

A particular solution contains 5mg/500mL of a drug. How many mg of the drug are contained in one teaspoon of the solution?

Answer 1

1 teaspoon = 5 ml

A 500 ml of solution contains 5 mg of drug.

100 ml of solution contains 1 mg of drug

For each ml of solution 1mg $\div$ 100 ml of solution = 0.01 mg of drug

5 ml of solution contains 0.01 $\times$ 5 = 0.05 mg of drug