I see that the math works if you start from the $30 and subract tip $2 and cost of the room at $28.
What I don't get, or can't figure out the error in my reasoning is why when you look at from the point of view if the guests it doesn't add up.
Guest A pays $10 gets $1 back = $9 paid
Guest B pays $10 gets $1 back = $9 paid
Guest C pays $10 gets $1 back = $9 paid
Total $27 + $2 tip =$29
I know the error is in my logic, I just can't figure out what mistake I am making. My brother-in-law, who teaches math, loves to taunt me with this.
Thanks,
Bill