A young male adult takes in about 5.0 10-4 m3 of fresh air during a normal

Question:

A young male adult takes in about 5.0 × 10-4 m3 of fresh air during a normal breath. Fresh air contains approximately 21% oxygen. Assuming that the pressure in the lungs is 1.0 × 105 Pa and that air is an ideal gas at a temperature of 310 K, find the number of oxygen molecules in a normal breath.