A canister contains 25 kPa of #CO_2#, 7.50 kPa of #N_2#, and 52.5 kPa of #O_2#. What is the total pressure within the canister?
This is simply the sum of the individual partial pressures...........and you can do the sum in your head.......to get
And this follows Dalton's law of partial pressures.....
This is an experimental gas law that has copious experimental support.
I think you can see from where the examiner pulled those figures.