quote "I would really love someone to show me how 150 passengers could be provided 2.5 hours worth of O2 at 39000 feet. "
low level fuel burn and resultant range is but one question posed by a depress burn. Those of you thinking of staying high to reduce resultant fuel burn (forgetting the pesky pax down the back and their O2 requirements) are not considering the very real danger of nitrogen coming out of solution in the bloodstream / joints .