155. If 500 is the multiple of 100 that is closest to x and 400 is the multiple of 100 that is closest to y, which multiple of 100 is closest to x + y ?
(1) x < 500
(2) y < 400
156. In the fraction x/y, x,y are all positive integers, what is the value of y?
(1) The least common denominator of x/y and 1/3 is 6
(2) x=1
以上两道题答案均为E，但是我居然看不懂题目，请大牛帮忙看看，解题过程什么样子啊？谢了（不好意思，怎么理解least common denominator ？）
1. X can be 451 to 499 according to the question and condition 1. Y can be 351 to 399 according to the question and condition 2. X+Y can be 802 to 898. The multiple of 100 closest to X + Y can be 800 or 900. Ans: E
2. Base on condition 1, y can be 2 or 6. Condition 2 is irrelevant. Ans : E
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发表于 2008-7-26 11:52:00
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