Marta bought several pencils, if each pencil was either a 23-cent pencil or a 21-cent pencil, how many 23-cent pencils did Marta buy?
1) Marta bought a total of 6 pencils 2) The total value of the pencils Mart bought was 130 cents.
答案：B If k and t are integers and k^2-t^2 is an odd integer, which of the following must be an even integer? I. k+t+2 II. k^2+2kt+t^2 III. k^2+t^2 答案：A In a certain year the United Nations' total expenditures were $1.6 billion. Of this amount, 67.8% was paid by the 6 highest-contributing countries, and the balance was paid by the remaining 153 countries. Was Country X among the 6 highest-contributing countries? 1) 56% of the total expenditures was paid by the 4 highest-contributing countries, each of which paid more than Country X. 2) Country X paid 4.8% of the total expenditures.
答案：E If m is a positive odd integer, what is the average (arithmetic mean) of certain set of m integers? 1) The integers in the set are consecutive multiples of 3 2) The median of the set of integers is 33.
23x＋21y＝130 当然，这个方程有无数对解，但是根据题意是买铅笔，只能取正整数解（because GMAC assumes that the pencil dealer won't sell a half pencil or 0.1 pencil），而正整数解正好只有一对啊，所以条件2单独就可以了。
If m is a positive odd integer, what is the average (arithmetic mean) of certain set of m integers? 1) The integers in the set are consecutive multiples of 3 2) The median of the set of integers is 33.
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2010-1-17 16:47:32
收藏
收藏
），而正整数解正好只有一对啊，所以条件2单独就可以了。
楼主