The setup
Dose per kg × Weight (kg) = Ordered dose
The dose per kg is always given in the question. The practice does not decide whether any amount is right for a real patient.
Pounds to kilograms
110 lb ÷ 2.2 = 50 kg
Carry the exact kg value forward. Round it only when the question says “Round the weight in kilograms to the nearest tenth before continuing.”
Advanced problems
Advanced questions add a second step: the ordered dose becomes the Desired value in D ÷ H × Q to find mL.