Question

to control an infection, a doctor recommends that a patient who weighs 92 pounds be given 320 milligrams of antibiotic. if the antibiotic is given proportionally according to the patients weight, how much antibiotic should be given to a patient who weighs 138 pounds? 400 milligrams 550 milligrams 480 milligrams 600 milligrams

Explanation:

Step1: Set up the proportion

Let \(x\) be the amount of antibiotic for \(138\) pounds. The proportion is \(\frac{320}{92}=\frac{x}{138}\).

Step2: Cross - multiply

\(92x = 320\times138\).

Step3: Solve for \(x\)

First, calculate \(320\times138 = 44160\). Then \(x=\frac{44160}{92}\).
\(x = 480\).

Answer:

\(480\) milligrams