机经讨论（十）

tongxun

关于第二题，大家可以参照pgclt兄弟的改写：
one store charge 10% sales tax for cloth and 5% sales tax for jourey, Alice各买了一样，use totally $109, the price of the bracelet EXCLUDING tax is $20, what is the price of the clothing inclu EXCLUDING tax? (answer: $80)
---------
在此，多谢pgclt兄弟！

brigittew

2，1.1x=109-20---->x=80.9

tongxun

brigittew：
  这么算，你的X只是买衣服的钱。

brigittew

但是提取求解的不是买衣服的钱吗？

tongxun

pgclt在题目改写中已经声明了：the price of the bracelet EXCLUDING tax is $20,
20是EXCLUDING tax 。

tongxun

感谢“困难是弹簧”兄弟的机经！并祝他下次成功！
-------------------------------------------
1、8 balls, 6 red and 2 black, chose two of them, at least one of the two is black 的概率。
answer: 1/2,1/4,1/8,13/28...
( should be: (1+2*C6,1)/C8,2=13/28)
------------------------
同意作者的答案：13/28
（C2，2 + C2，1 * C6，1）/C8，2 =13/28
==============
2、另外一题也挺饶人：one store charge 10% sales tax for cloth and 5% sales tax for jourey, Alice各买了一样，use totally $109, the price of the bracelet including tax is $20, what is the price of the clothing including tax? (answer: $80) (trick: pay attention to "tax" and "sales tax")
---------------------------------------
80。
答案的得出：大家可以参照pgclt兄弟的改写：
one store charge 10% sales tax for cloth and 5% sales tax for jourey, Alice各买了一样，use totally $109, the price of the bracelet EXCLUDING tax is $20, what is the price of the clothing inclu EXCLUDING tax? (answer: $80)

[此贴子已经被tongxun于2002-10-1 3:20:25编辑过]