不好意思，请教一道小六数学题

parsingapore

今天给女儿做一份去年名校考卷，这道题是最后一题她做了很久做不出，我说休息去吧，我来试试看，结果涂了一阵没涂出来。请各位帮帮忙。题目是这样的：

Dolly had 80 more stickers than Jenny. Dolly gave 25% of her stickers to Jenny. Jenny in return give 60% of her stickers to Dolly. In the end,Dolly had 100 stickers more than Jenny. How many stickers did Dolly have at first?

先谢谢帮忙。

春满月圆

小春满月圆的答案是：116(dolly)，36(Jenny)

parsingapore

春满月圆 发表于 29-1-2011 23:23
小春满月圆的答案是：116(dolly)，36(Jenny)

小春满月园好厉害。答案是正确的。可以告诉我怎么做吗？多谢了。

春满月圆

If Dolly had 100u+80,then Jenny would have 100u.
After giving away 25% of her stickers to Jenny,she will left 75u+60 (60是这么来的：80/4*3)
Jenny will then have 125u+20.
After Jenny gave 60% of her stickers to Dolly,she will have 50u+8,while Dolly will have 150u+72.
Thus,100=100u+64.
So,1u=(100-64)/100=0.36
Dolly=0.36*100+80

or

Dolly  :100u+80
Jenny:100u
____________________________
Dolly  :75u+60
Jenny:125u+20
____________________________
Dolly  :150u+72
Jenny:50u+8
____________________________
1u=(100-64)/100=0.36

春满月圆

上面是小春满月圆的步骤~~~

他的体会：题容易，打出来好费力啊~~~

人家跃跃欲试好几回了
今天，终于逮到机会了
还要谢谢你哈~~~

parsingapore

春满月圆 发表于 29-1-2011 23:34
If Dolly had 100u+80,then Jenny would have 100u.
After giving away 25% of her stickers to Jenny,she  ...

谢谢，打印出来了，好好研究一下。

春满月圆

parsingapore 发表于 29-1-2011 23:32
小春满月园好厉害。答案是正确的。可以告诉我怎么做吗？多谢了。

小春满月圆又编辑了一下，觉得那样更清楚~~~

parsingapore

春满月圆 发表于 29-1-2011 23:43
小春满月圆又编辑了一下，觉得那样更清楚~~~

小老师真认真，更清楚我也要（太贪婪了）。我觉得我得请客了。

春满月圆

parsingapore 发表于 29-1-2011 23:51
小老师真认真，更清楚我也要（太贪婪了）。我觉得我得请客了。

见4楼~~~

春满月圆

小春满月圆说了，真要请的话，麦当劳就行了。。。