2x+30%x=9.2 ==> 2.3x = 9.2 ==> x = 4 (5/12) / (2/3 - 1/4) = 5 / [(2/3 - 1/4) ×12] = 5 / [2/3 * 12 - 1/4 * 12] = 5 / [8 - 3] = 5/ 5 = 1
