in a certain apartment building , there are one - bedroom and two - bedroom apartments . the rental prices of the apartment depend on a number of factors , but on average , two - bedroom apartments have higher rental prices than do one - bedroom apartments . let r be the average rental price for all apartments in the building . if r is $ 5,600 higher than the average rental price for all one - bedroom apartments , and if the average rental price for all two - bedroom apartments is $ 10,400 higher that r , then what percentage of apartments in the building are two - bedroom apartments ?