4a + 5b = 32*60 (1) (minutes to make) 3a + 5b = 1740 (2) (material cost) To solve the system, use the Elimination method. For it, subtract eq(2) from eq(1). You will get 4a - 3a = 32*60 - 1740 = 180. a = 180. Then from eq(2), 5b = 1740 - 3*180 = 1200, b = 1200/5 = 240. ANSWER. 180 switches of the type A and 240 switches of the type B.