FCA1-0244

A patient admitted to the hospital is on oxygen via a venturi mask. The air entrainment ratio is 1:9 i.e. 1 litre of 100% oxygen from the source entrains 9 litres of air from the atmosphere). The flow rate of 100% oxygen is 6L/minute. Based on the given data which of the following value approximates the oxygen concentration delivered to the patient?