求解数学题，谢谢了！！

wanderal · 发表于 2011-6-29 23:27:17

是几天做题遇到的，希望大家可以帮忙分析分析，谢谢了O(∩_∩)O
一.Is the hundredths digit of the decimal d greater than 5?
(1) the tenths digit of 10d is 7
(2) the thousandths digit of d/10 is 7
答案：each along is suficient

二.for a certain race, 3team were allowed to enter 3members each. A team earned
6-N points whenever one of its members finished in Nth place, where 1≤N≤5. there were no ties, disqualifications, or with drawals. if no team earned more than 6 points, what is the least possible score a team could have earned?
答案：3

三 Amy's grade was the 90th percentile of the 80 grades for her class. of the 100 grades from another class, 19 were higher than Amy's, and the rest lower. if no other grade was the same as Amy's grade, then Amy's grade was what percentile of the grades of the two classes combined?
答案：85th

四 if n is a positive integer and r is the remainder when n²-1 is divided by 8, what is the value of r?
(1)n is odd
(2)n is not divisible by 8
答案：both together are not sufficient

rikihsu · 发表于 2011-6-29 23:58:45

1. 设数字d为a.bc
(1) 10d=ab.c c=7 sufficient
(2) d/10=0.abc c=7 sufficient

2. 得分只有5,4,3,2,1 总分15分,最高分不过6假设最高分为6, 15-6-6=3

3. amy在80个分数里是90% percentile 那说明有有72个人比她差，在另外个班级有81个人比她低。
那么一共有153个分数比她低在180个分数里。所以153/183=85%

4. 这个直接代数字进去比较方便哈哈。答案有问题?A是sufficient. remainder都是0呀

wanderal · 发表于 2011-6-30 08:38:34

谢谢你啦，O(∩_∩)O

wanderal · 发表于 2011-6-30 08:55:06

第四题，代数进去都是零，那就是1.2.都sufficient了

rikihsu · 发表于 2011-6-30 12:48:47

(2)not sufficient哦

求解数学题，谢谢了！！

谢谢！

是啊

所属分类: GMAT考试

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