Robitussin DM contains 100 mg of guaifenesin per 1 teaspoon. How many milligrams of guaifenesin are in 10 mL?
A.
200 mg
B.
100 mg
C.
75 mg
D.
50 mg
The correct answer and Explanation is :
To solve this, we need to determine how many milligrams (mg) of guaifenesin are in 10 mL of Robitussin DM based on the provided information that 100 mg of guaifenesin is in 1 teaspoon (5 mL).
Step-by-Step Calculation:
- Determine the concentration of guaifenesin in 1 mL:
- We know that 5 mL (1 teaspoon) contains 100 mg of guaifenesin.
- Therefore, the concentration of guaifenesin per mL is: [
\text{Concentration per mL} = \frac{100 \, \text{mg}}{5 \, \text{mL}} = 20 \, \text{mg/mL}
]
- Calculate the amount of guaifenesin in 10 mL:
- Now that we know the concentration is 20 mg/mL, we can calculate how much guaifenesin is in 10 mL: [
\text{Amount in 10 mL} = 20 \, \text{mg/mL} \times 10 \, \text{mL} = 200 \, \text{mg}
]
Correct Answer:
- The correct answer is A. 200 mg.
Explanation:
The concentration of guaifenesin in Robitussin DM is 100 mg per 5 mL, which simplifies to 20 mg per 1 mL. Since the problem asks how much guaifenesin is in 10 mL, you multiply the concentration (20 mg/mL) by the volume (10 mL). This gives you 200 mg of guaifenesin in 10 mL.
This is a basic example of unit conversion, where you use the given concentration to calculate the amount of a substance in a different volume. It’s important to always keep track of units (mg and mL) and understand the relationship between the given values to solve dosage-related problems correctly.