What percent of a drug is contained in a mixture of powder consisting of 0.5 kg, containing 0.038% of a drug, and 10 kg, containing 0.043% of a drug?

The percentage of the drug in the mixture is 0.043%.

Explanation:

0.5 kg contains 0.038% of a drug.

Mass of the drug = 0.038% of 0.5

                            = × 0.5

                            = 0.00019

                            = 1.9 ×

10 kg contains 0.043% of the same drug.

Mass of the drug = 0.043% of 10

                            = × 10

                            = 0.0043

                            = 4.3 × kg

Total mass of drug = 0.00019 + 0.0043

                               = 0.00449

                               = 4.49 × kg

Total mass of mixture = 0.5 kg + 10 kg

                                     = 10.5 kg

Percentage of the drug in the mixture = × 100

                                                               = 0.04276%

The percentage of the drug in the mixture is 0.043%.