Toby's Sportshouse produces two models of bikes, the RB (road bike) and the MB (mountain bike). Bike revenue (in thousand pesos) for the firm is nonlinear and is stated as (number of RBs)(5 0.2 number of RBs) + (number of MBs)(7 0.3 number of MBs). Toby's has 80 labor-hours available per week in its paint shop. Each AB requires 2 labor-hours to paint and each YZ requires 3 labor-hours. Formulate the mathematical model of this nonlinear production planning problem to determine how many RB and MB bikes should be produced per week at Toby's.