A factory produces three types of products: A, B, and
C. The ratio of the number of units produced for A, B, and C is initially 3:4:5. After a revision in the production plan, the production of A is increased by 20%, the production of B is decreased by 10%, and the production of C remains unchanged. If the factory initially produced 16,200 units in total, what is the total number of units produced after the changes?

Let the initial production of A, B, and C be 3k, 4k, and 5k respectively, where k is the common multiple. The total production is 16,200 units, so: 3k + 4k + 5k = 16,200 12k = 16,200 k = 1350 Thus, the initial production is: A = 3 * 1350 = 4050 units B = 4 * 1350 = 5400 units C = 5 * 1350 = 6750 units After the changes: A’s new production = 4050 * 1.20 = 4860 units B’s new production = 5400 * 0.90 = 4860 units C’s production remains unchanged = 6750 units The total production after the changes is: 4860 + 4860 + 6750 = 16,470 units Thus, the total production after the changes is 16,470 units Answer: a) 16,470