to get the answer, use the value that has two units because that's your conversion factor (what is used to convert).
conversion factor--> 450 mg/Kg
this value tells us that 450 mg= 1 Kg
use it so the units cancel (what you converting from in the denominator, Kg, what you converting to in the numerator, mg)
Arnold
45 Kg x (450 mg/ 1 kg)= 20250 mg
Harold
96 Kg (450 mg/ 1 Kg)= 43200 mg
