Question

The Doctor writes a prescription for 75 mg of Diphenhydramine to be mixed with 0.25 oz of Shea Butter Cream. Shea Butter and Eucerin Cream have a 1:3 ratio. How much Eucerin Cream would you use in 100mg of Diphenhydramine?

Answer 1

According to the prescription we need 0.25 oz of Shea Butter Cream for 75 mg of Diphenhydramine. So, for 100 mg of Diphenhydramine we will need:

$$m = \frac{100 \cdot 0.25}{75} = \frac{1}{3} \text{ oz. of Shea Butter Cream}.$$

And we know that Shea Butter and Eucerin Cream have a 1:3 ratio. So, We will need $\frac{1}{3} \cdot 3 = 1$ oz. of Eucerin Cream.

Answer: 1 oz.