Tha is interesting, Sylvan. Not being “in” on the technojargon of several hundred years of plumbing, I would have to guess at the meaning of “Suppose the invert of the elevation is 22.66 AT a pitch of 5% over a hundred foot run what would be the elevation of the basement.”
I would guess that flipping an elevation over would be inverting the elevation, in other words “depth.” Since you pitch downward (another guess because it is logical) 5%, the increase in depth is 5 out of 100, in this case, 5 feet. The next guess would be that the depth of the sewer main is at 27.6 feet and the end of the pitched pipe meets it at 22.6 feet above the main because 22.6 plus 5 equals 27.6. If you don’t know the trade jargon you can never be sure. Lucky that an apprentice gets a chance to practice in class.