求助两道数学题

Sunyidan1988 · 发表于 2009-12-9 06:41:09

For a finite sequence of nonzero numbers, the number of variations in sigh is defined as number of pairs of consecutive terms of the sequence for which the product of the two consecutive terms is negative. what is the number of variations in sign for the sequence 1,-3,2,5,-4,-6
a.one b.two c.three.d.four.e.five 答案是c

Sunyidan1988 · 发表于 2009-12-9 06:45:47

公司两种机器R，S, 做同一工作R36小时，S18小时，如果用同数量的两种机器做一个工作在两小时内完成了，用了多少台R?答案是6

sprtng · 发表于 2009-12-9 07:01:09

For a finite sequence of nonzero numbers, the number of variations in sigh is defined as number of pairs of consecutive terms of the sequence for which the product of the two consecutive terms is negative. what is the number of variations in sign for the sequence 1,-3,2,5,-4,-6
a.one b.two c.three.d.four.e.five 答案是c

-- by 会员 Sunyidan1988 (2009/12/9 6:41:09)

意思就是说让你找这个数列当中，有几组相邻的组合是正负组合？答：　三组：　1,-3　－３,2　　5,-4

sprtng · 发表于 2009-12-9 07:03:14

公司两种机器R，S, 做同一工作R36小时，S18小时，如果用同数量的两种机器做一个工作在两小时内完成了，用了多少台R?答案是6

-- by 会员 Sunyidan1988 (2009/12/9 6:45:47)

1/(x/36 + x/18) = 2 => 1/(3x/36) = 2 => 36/3x = 2 => 3x = 18 => x = 6

Sunyidan1988 · 发表于 2009-12-9 07:35:11

我对我数学真的没信心了……谢谢啦！

sprtng · 发表于 2009-12-9 08:22:03

我对我数学真的没信心了……谢谢啦！

-- by 会员 Sunyidan1988 (2009/12/9 7:35:11)

做数学题切忌心急, 慢慢来，看准题，特别是像第一道那么绕口的。

对自己有信心点，没问题的！

求助两道数学题

下一道本人数学不要见笑了

太感谢了！

所属分类: GMAT考试

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