Used when something is said in an obvious manner when it is not obvious to others. Pffh Duh is then stated as a joke mimicking the speaker because it truly was not obvious.
Teacher: You do not need to memorize all fifty equations because you can derive these formulas all from this first formula. Its very simple to derive each equation and then you can obviously create a system of equations with every derived equation to create the final equation.
Students: *Whisper to each other* Pffh Duh!
Students: *Whisper to each other* Pffh Duh!
by Kentviknesh October 2, 2016