How do I work this out Rhys when walking takes an average of 16 breathes per minute and exchanges 1.5 litres of air at each breath. The inspired air contained 20 oxygen and the expired air contained 1?

To calculate the total oxygen exchanged while walking, first determine the total volume of air exchanged per minute by multiplying the breaths per minute (16) by the volume of air per breath (1.5 liters), resulting in 24 liters of air exchanged. Next, calculate the amount of oxygen in the inspired air: 20% of 24 liters equals 4.8 liters of oxygen inhaled. For the expired air, if it contained 1% oxygen, that would be 0.24 liters of oxygen expelled. Therefore, the net oxygen used during walking is 4.8 liters (inhaled) - 0.24 liters (exhaled) = 4.56 liters of oxygen utilized per minute.