求助数学啊

xiahuistacy · 发表于 2010-1-8 16:10:50

Q8:

Which of the following fractions has a decimal equivalent that is a terminating decimal?

选项有10/189 15/196 16/225 25/144 39/128 答案是E 但是我不知道从何解题

Q9:

Company S produces two kinds of stereos: basic and deluxe. Of the stereos produced by Company S last month,
were basic and the rest were deluxe. If it takes as many hours to produce a deluxe stereo as it does to produce a basic stereo, then the number of hours it took to produce the deluxe stereos last month was what fraction of the total number of hours it took to produce all the stereos?

这个题目答案是 7/17 我也不知道怎么解

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Q19:

This year Henry will save a certain amount of his income, and he will spend the rest. Next year Henry will have no income, but for each dollar that he saves this year, he will have 1 + r dollars available to spend. In terms of r, what fraction of his income should Henry save this year so that next year the amount he was available to spend will be equal to half the amount that he spends this year?

这个题目答案是1/(2r+3) 不知道怎么做

请大家帮忙

zhfan · 发表于 2010-1-8 17:28:46

Q19 那一题
假设总收入为 I，这个fraction为X, 根据题意，省下的钱是 X*I，放到第二年变为X*I(1+r) ，这笔钱就是the amount he was available to spend
然后，省下X*I，那么今年花掉的部分就是（I-X*I); half the amount that he spends this year=(1/2) *(I-X*I)
由此，可以列出
X*I(1+r)=(1/2) *(I-X*I)
展开之后，把X放到左边，右边的I可以消去得1/(2r+3)
自己算一下就知道啦！

prayer · 发表于 2010-1-8 17:46:45

第9题好像题目不全。第8题求有限小数是那个。就是要找分母是2或5的，只有E

jianxinwang · 发表于 2010-1-8 18:03:30

22个学生，每人至少有一直铅笔，问教室里有没有2个或2个以上学生手里有3根铅笔
条件一，一个有250支铅笔
请问此题的答案。（是一月六号的考题）
谢谢！

求助数学啊

所属分类: GMAT考试

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