问些题目，望高手指点，数学实在很差

miguel29

1,if each photocopy of a manuscript cost 4 cents per page, what is the cost, in cents, to reproduce x copies of an x-page manuscript? 答案是 4x2
这题能解释下怎么做的吗？题目看了也不太理解啊

2，Of a group of people surveyed in a political poll, 60 percent said that they would vote for R. Of these who said they would vote for R.90 percent actually vote for R. and of these who did not say that they would vote for R. 5 percent actually voted for R. What percent of the group voted for R? 答案是：56%
解释下好吗？也是题目也看不太懂，关系好乱啊

3 A student responded to all  of the 22 questions on a test and received a score of 63.5. If the score were derived by adding 3.5 points for each correct answer and deducing 1 point for each incorrect answer, how many questions did the student answer incorrectly? 答案是4
这种类型的题目都不太会，麻烦指点下

4，In company X, 30% of employees live over ten miles from work and 60 percent of the employees who live over ten miles from work are in car pools. if 40% of the employees of company X are in car pools, what percent of the employee of company X live ten miles or less from work and area in car pools? 答案是 22%

题目有点多，不好意思，没人教，只有考CD啦。。谢谢啦

2011catcat

[quote]
1,if each photocopy of a manuscript cost 4 cents per page, what is the cost, in cents, to reproduce x copies of an x-page manuscript? 答案是 4x2
这题能解释下怎么做的吗？题目看了也不太理解啊

请问lz这答案是4乘以2还是4x^2啊？如果说是4x^2那还明白。
题目说每一份手稿的一份影印件要4美分嘛，那么有x份手稿的x份影印件，要花费就是4x^2咯~

2，Of a group of people surveyed in a political poll, 60 percent said that they would vote for R. Of these who said they would vote for R.90 percent actually vote for R. and of these who did not say that they would vote for R. 5 percent actually voted for R. What percent of the group voted for R? 答案是：56%
解释下好吗？也是题目也看不太懂，关系好乱啊
这种题一定要分好类，画图。A类；说会投票给R的有60%，但是实际有90%的人投了
                                      那么B类：说不会投票给R的有就有（1-60%）=40%的人咯，但是实际上有
                                                       5%的人投了票
那么求投给R的有多少人：关系就已经很明显了，就是60%*90%*+40%*5%=56%
lz做这种题头脑一定要清晰每一类的关系哦，最好在草稿画出来

3 A student responded to all  of the 22 questions on a test and received a score of 63.5. If the score were derived by adding 3.5 points for each correct answer and deducing 1 point for each incorrect answer, how many questions did the student answer incorrectly? 答案是4
这种类型的题目都不太会，麻烦指点下
这题应该是这样吧，直接设做错的题目数为x，关系式就出来了 3.5（22-x)-x=63.5
但是我算出的x=3哦，思路这样应该没错的呀~但是答案.......

4，In company X, 30% of employees live over ten miles from work and 60 percent of the employees who live over ten miles from work are in car pools. if 40% of the employees of company X are in car pools, what percent of the employee of company X live ten miles or less from work and area in car pools? 答案是 22%
题目有点多，不好意思，没人教，只有考CD啦。。谢谢啦
这种题与第二题同属一类，还是分类，画venn图的问题
题目说：住在大于10m的员工有30%嘛，其中30%里面有60%的坐车。全公司有40%的员工坐车，
问住在等于，小于10m的员工有多少%坐车。
这好像比第二题更简单一点，要好理解一点的话，就假设全公司有a人，
                直接就出来 40%a-30%a*60%=22%a咯，就22%
一定要读好题，理解好哦~~

dingacat777

第一题，可能因为是那个复印，一页纸是两面，所以要乘以2

第二题，60%×90%+(1-60%)*5%=54%+2%=56%

LZ问的很多题，和第2题都是类似的，安下心来好好看一下，都不难的，LZ好运～

miguel29

清楚。。。非常感谢。至于第一题，有可能是他答案打印的时候打错了，它答案就是写4x2 ,觉得楼主的解法正确啊