How much the AC runs is dependent on your outside temperature and if you are parked in direct sun. In our 33C, if it is 95 degrees outside and we are parked in direct sun with our shades open, our two ACs will run nearly constantly to keep the temperature down at 75. The ACs will also cycle so as to not freeze up.
We have found, when parked in direct sunlight and with outside temperatures at 75, the RV heats up quickly. To keep the temps down and the AC not running so much, park in the shade, pull down the shades, especially the front, open a vent in the roof to allow heat to escape, and crack a few windows to allow in a breeze.