Giải quyết các phương trình đầu tiên cho x cho x = 50n. Sau đó, thay thế 50n cho x trong phương trình thứ hai đưa ra sau đây có thể được giải quyết cho n: 50n + 90 55 = n +1 55 (n + 1) = 50n + 90 55n + 55 = 50n + 90 5n = 35 n = 7 nhân cả hai bên (n + 1) phân phối trừ 55 50n và 55 của cả hai bên chia cả hai vế cho 5 | Data Sufficiency Answer Explanations 142. What amount did Jean earn from the commission on her sales in the first half of 1988 1 In 1988 Jean s commission was 5 percent of the total amount of her sales. 2 The amount of Jean s sales in the second half of 1988 averaged 10 000 per month more than in the first half. Arithmetic Applied problems Let A be the amount of Jean s sales in the first half of 1988. Determine the value of A. 1 If the amount of Jean s sales in the first half of 1988 was 10 000 then her commission in the first half of 1988 would have been 5 10 000 500. On the other hand if the amount of Jean s sales in the first half of 1988 was 100 000 then her commission in the first half of 1988 would have been 5 10 0000 5 000 NOT sufficient. 2 No information is given that relates the amount of Jean s sales to the amount of Jean s commission NOT sufficient. Given 1 and 2 from 1 the amount of Jean s commission in the first half of 1988 is 5 A. From 2 the amount of Jean s sales in the second half of 1988 is A 60 000. Both statements together do not give information to determine the value of A. Therefore 1 and 2 together are NOT sufficient. The correct answer is E both statements together are still not sufficient. 143. The price per share of Stock X increased by 10 percent over the same time period that the price per share of Stock Y decreased by 10 percent. The reduced price per share of Stock Y was what percent of the original price per share of Stock X 1 The increased price per share of Stock X was equal to the original price per share of Stock Y. 2 The increase in the price per share of Stock X 10 was 11 the decrease in the price per share of Stock Y. Arithmetic Algebra Percents Applied problems Equations Let x represent the original price per share of Stock X. The amount that Stock X increased per share can then be represented by and the increased price per share of Stock X by . Let y represent the original price per share of Stock Y. The amount .
