Suppose the wall area to be painted in each room is x, the walls painted by three first-level technicians are 8X-50, and the walls painted by five second-level technicians are 10X+40. Because the first-class technician draws more 10 square meter a day than the second-class technician, according to this difference, the formula is (8x-50)/3 = (10x+40)/5+.