A bag can hold 2.5 L of \( 0.9 \% \) sodium chloride solution. If four patients are given 350 mL each of the solution, how much is left in the original bag? Express the answer in millilitres. Solution left \( =\square \mathrm{mL} \)

1. Convert the bag’s capacity to millilitres: \[ 2.5\ \text{L} = 2500\ \text{mL} \] 2. Calculate the total volume given to the four patients: \[ \text{Total volume administered} = 4 \times 350\ \text{mL} = 1400\ \text{mL} \] 3. Find the remaining volume in the bag by subtracting the administered volume from the bag's capacity: \[ \text{Solution left} = 2500\ \text{mL} - 1400\ \text{mL} = 1100\ \text{mL} \] The final answer is: \[ \boxed{1100\ \text{mL}} \]