a math question from Lisa

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Hey there I am new here , so don't know how to deal with some of the function but anyway I like this site quite well .... here is one maths pro that puzzled me , in fact, many maths pros confuss me ...... need your kindly help thank you ^^ from Lisa in SH 3、x,y,k>0 ,( x/(x+y))^10 + ( y/(x+y) )^20 = k ， x【讨论】 N：附上老机经： 已知正整数x y k, x答案：18 （15< <20） R：式子=(10x+20y)/(x+y)=10+10/(x/y+1)=k,因为0

lisaislisa

sorry
I mean that I can get the answer with the cue but always meet difficulties when I am 'fighting ' against it all by myself......

I need practice you will say , right ? a long long way to go........ i know

tongxun

lisa：我不明白你的意思。

lisaislisa

btw , was that you who sent me the request by oicq ?
nice meeting ya ^^

lisaislisa

thanks for your explanation ^^
I can be lead to the correct answer from you but as I was dealing with the problems by meself I got no idea.......

tongxun

由于每天的家长数最多是5个，假设周三是5个，则周2最多4人。
20-9=11，假设周一、四最多人，则两天是10人，11-10=1，则周五至少有1人

lisaislisa

another one.....i faited as i've read the question.....

21、DS:20个家长选择周一到周五开家长会,周三的家长多于周二的家长,问周五是否有至少一个家长选择
1)没有一天的家长数超过5个 2)周三的家长多余周一的
【确定】A

lisaislisa

hehe ...thx ^^

tongxun

不是你笨！是我们的题目还是没写清楚。
在题目的选项中有几个可供选择：
15、18、20、30、50
所以，选18。

lisaislisa

呜呜, 丫头笨还是不懂...;( why 15 thank you all ^^ espeicially for kitty..... and at last I found the forum here ..... and get your answers... good luck , from Lisa in SH