Hollow fiber membranes are a new technology used for separating gases. A porous membrane is used to concentrate the amount of oxygen in the product stream. The feed stream is air (21% O2, 79% N2). The concentrated stream is 30% O2 and 70% N2. If the total mole of waste stream is 75% of that of the input stream, the input stream is 100 mol. What is the molar composition of oxygen in the waste stream?