Answer:
127.28 mmHg
Explanation:
The molar fraction of oxygen in dry air at 760 mmHg is 20.9%. This molar fraction is not affected too much by the height, so it may be taken as a constant. The partial pressure of oxygen may be calculated as:
[tex]P_{O_{2}}=y_{O_{2}}*P[/tex]
So, if the total pressure is 609 mmHg,
[tex]P_{O_{2}}=0.209*609=127.28[/tex] mmHg.