ABS plastic is a tough, hard plastic used in applications requiring shock resistance. The polymer consists of three monomer units: acrylonitrile (C3H3N), butadiene (C4H6), and styrene (C8H8). A sample of ABS plastic contains 8.80% N by mass. It took 0.605 g of Br 2 to react completely with a 1.20-g sample of ABS plastic. Bromine reacts 1:1 (by moles) with the butadiene molecules in the polymer and nothing else. What is the percent by mass of acrylonitrile and butadiene in this polymer?