Answer: 480 milligrams
Explanation:
We can solve this by using direct proportion whereby y = kx
where,
x = patient's weight = 92 pounds
k = constant
y = milligrams of antibiotics = 320
Using y = kx
320 = 92k
k = 320/92
k = 3.4782609
The antibiotic that should be given to a patient who weighs 138 pounds will be:
y = kx
y = 3.4782609 × 138
y = 480 milligrams
The antibiotic that should be given to a patient who weighs 138 pounds is 480 milligrams.