Question

The dosage of a cold medication is 2 mg for every 60 lb of body weight. How many milligrams of this medication are required for a person who weighs 105 lb?

Answer 1

Based on the problem, for every 60 lb of body weight, the dosage must be 2mg. We can infer from this statement that the greater the weight is, the more dosage of the medication must be taken.

We can see that the number of dosage is directly proportional to the weight of the person. The formula for this is:

`(2mg)/(60lb)=(x)/(105lb)`

From this, we can now solve for x which is the dosage for 105-lb person.

To solve x, first let's cross multiply.

`\begin{gathered} 2*105=60* x \\ 210=60x \end{gathered}`

Then, divide both sides by 60.

`\begin{gathered} (210)/(60)=(60x)/(60) \\ 3.5=x \end{gathered}`

Therefore, a person that weighs 105 lb must take 3.5 mg of the cold medication.