A hot-air balloon has a volume of 2200 $\mathrm{m}^{3} .$ The balloon fabric (the envelope) weighs 900 $\mathrm{N} .$ The basket with gear and full propane tanks weighs 1700 $\mathrm{N}$ . If the balloon can barely lift an additional 3200 $\mathrm{N}$ of passengers, breakfast, and champagne when the outside air density is $1.23 \mathrm{kg} / \mathrm{m}^{3},$ what is the average density of the heated gases in the envelope?