High School

You are working in a pharmacy and need to make a table to help with dosage amounts for a certain drug. The recommended dosage is 40 milligrams per 2.2 pounds of body weight, divided into three daily doses taken every 8 hours. You need entries for children weighing 10 pounds, 15 pounds, and 30 pounds. The drug comes in a [tex]200 \, \text{mg} / 5 \, \text{ml}[/tex] formula. If 1 teaspoon = 5 ml, how many teaspoons are required for each entry? Round your answer to the nearest [tex]\frac{1}{4}[/tex] teaspoon.

A. [tex]1, 1 \frac{1}{2}, 2 \frac{3}{4}[/tex]
B. [tex]181, 272, 545.5[/tex]
C. [tex]10, 15, 30[/tex]
D. [tex]4 \cdot 5, 7, 13[/tex]

Answer :

We are given that the recommended dosage is
[tex]$$40\text{ mg for each }2.2\text{ pounds of body weight},$$[/tex]
divided into three doses each day (taken every 8 hours). In addition, the drug is provided with a formulation of
[tex]$$200\text{ mg per }5\text{ ml},$$[/tex]
and since
[tex]$$5\text{ ml} = 1\text{ teaspoon},$$[/tex]
each teaspoon contains 200 mg of the drug.

For each child's weight, we follow these steps:

1. Calculate the dose in mg per dose:
For a child weighing [tex]$W$[/tex] pounds, the medication per dose (in milligrams) is given by
[tex]$$\text{Dose in mg} = \left(\frac{W}{2.2}\right) \times 40.$$[/tex]

2. Convert the dose from milligrams to teaspoons:
Since each teaspoon contains 200 mg, the dose in teaspoons is
[tex]$$\text{Teaspoons (raw)} = \frac{\text{Dose in mg}}{200}.$$[/tex]

3. Round up to the nearest [tex]$\frac{1}{4}$[/tex] teaspoon:
After computing the raw teaspoons, we round up (i.e. use the minimum amount that is not less than this value) to the next [tex]$\frac{1}{4}$[/tex] teaspoon increment.

Now, let’s apply these steps to the given weights.

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For 10 pounds:

1. Calculate the dose in mg:
[tex]\[
\text{Dose}_{10} = \left(\frac{10}{2.2}\right) \times 40 \approx 181.82\text{ mg}.
\][/tex]

2. Convert to teaspoons:
[tex]\[
\text{Teaspoons}_{10} = \frac{181.82}{200} \approx 0.91\text{ teaspoons}.
\][/tex]

3. Round up to the nearest [tex]$\frac{1}{4}$[/tex] teaspoon:
The next quarter increment after 0.91 is 1.00 teaspoon.

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For 15 pounds:

1. Calculate the dose in mg:
[tex]\[
\text{Dose}_{15} = \left(\frac{15}{2.2}\right) \times 40 \approx 272.73\text{ mg}.
\][/tex]

2. Convert to teaspoons:
[tex]\[
\text{Teaspoons}_{15} = \frac{272.73}{200} \approx 1.36\text{ teaspoons}.
\][/tex]

3. Round up to the nearest [tex]$\frac{1}{4}$[/tex] teaspoon:
The next quarter increment after 1.36 is 1.50 teaspoons.

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For 30 pounds:

1. Calculate the dose in mg:
[tex]\[
\text{Dose}_{30} = \left(\frac{30}{2.2}\right) \times 40 \approx 545.45\text{ mg}.
\][/tex]

2. Convert to teaspoons:
[tex]\[
\text{Teaspoons}_{30} = \frac{545.45}{200} \approx 2.73\text{ teaspoons}.
\][/tex]

3. Round up to the nearest [tex]$\frac{1}{4}$[/tex] teaspoon:
The next quarter increment after 2.73 is 2.75 teaspoons.

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Thus, the required teaspoons for each of the entries are:
- 10 pounds: 1 teaspoon
- 15 pounds: 1½ teaspoons
- 30 pounds: 2¾ teaspoons

This corresponds to answer option A:
[tex]$$1, \; 1\frac{1}{2}, \; 2\frac{3}{4}.$$[/tex]