I had a professor at university who would have considered that a perfectly acceptable tutorial question. We would have to make all of the estimates and assumptions ourselves.

I almost want to try and calculate the various points of interest (uncomfortable, dangerous, unconscious, and dead). The critical limits would be CO2 level related. CO2 would likely become deadly before all the oxygen was used up.

It would also be interesting to work out the difference between the child sitting calmly Vs desperately clawing at the inside of the dome with bloodied fingers.