At first, we need to find the Dosage for Ms. Campbell's weight
We will do that using the ratio method

By using the cross-multiplication

Now, we will find the number of milliliters of medicine when using the concentration of 250 mg/5 mL

By using the cross-multiplication

Round it to the nearest 1 decimal place, then
y = 21.3 mL
The answer is 21.3 mL