littlegal

55.圆柱X， 2R， H 与圆柱Y R，2H 的表面积差用R和H表示是多少？
【确认】3/2派R^2+派RH

I think the answer is 6 Pin R^2

littlegal

2、100个某东西，买来的时候30元一个，全部卖出后赢利1500刀元。其中N个以每个50元卖出，其余的以每个X刀元卖出。问X LESS THAN 40？
1）N > 60
2) N < 80
【确认】A


Does anyone know why the answer is A?

Thank you so much!

littlegal

3.(1.000001X0.99999)-(1.000002X0.999998) (4次)
【确认】.-3*(10)^(-10)


I think the answer is supposed to be 3X10^-10

Does anyone have the same answer as I do?

yvonnezenith

愿闻其详，题目已经看晕了。

lisaislisa

about the problem on tax fees ,
I met this problem today !
but little difference , the difference is that c is the change that recieved after paying , therefore it is
x(1+p)+c=20
I chose B , but my math is ....49  

mingja

Usually fees are not subject to sales tax

Sales tax are applicable to item purchased.  

If x is the purchase price, then x + xp/100+c=$20

yvonnezenith

to joywzy
you may be a little careless.
not 20/(1+6), but 20/(1+0.06).

HOWEVER,
5． 有某个地方的用电量1993年是3.2million 而1993年是3.4million，他们用柱壮图来表示，用电量与柱高成正比例，1993年的柱高是2cm，问：1994年的柱高是多少？
答案：3.2/2=3.4/x x=9/4
FROM THE ABOVE CALCULATION, I GOT 17/8.

[此贴子已经被作者于2003-1-21 23:48:58编辑过]

joywzy

3某东西sell at price 20 dollors, including tax, 税率是百份P，还包括其他什么费less than C，好象问：不含税的部分小于15吗？A：P等于6，B：C等于5 --------------------------------- (x+c)(1+p)=20 if c=5 , whatever p is , ( even is 0 ) x<=15 , but from the text , p can not be 0 , since there is tax payment ( or you will be fined ....kidding ) so B is sufficient In this aspect, i agree with u but when p=6 or mean tax rate 6% => x+c= 20/7=2.8, and X>0,c>0=>0X,15 so i think A is sufficient I guess A,B is both sufficient Did i make any mistakes?

yvonnezenith

恳请大虾指点迷津。
14)During a trans-atlantic trip ticket, 20% held round-trip and with cars aboard, 60% held round trip ticket with no car aboard. ask the total percentage of persons held round-trip ticket.
30%, 60%, 66-1/3 %
hope somebody help me. No answer is bigger than 66.3333%
------------------------------------------------
[思路]no idea...
[08]
我算的是50%， 不知道对不对
我是这样算的：
60%的人有R but no C , 所以有40% 的人有R&C, 设有R的人数为X
40%X = 20% X=50%

如果这样理解，60%的是有R的60%，20%是所有TICKET的20%？题目中没有说明啊。
我希望了解一下我这样理解此类题目是否对头。恳请大虾指点迷津。

[此贴子已经被作者于2003-1-21 23:17:26编辑过]

lisaislisa

3某东西sell at price 20 dollors, including tax, 税率是百份P，还包括其他什么费less than C，好象问：不含税的部分小于15吗？A：P等于6，B：C等于5 --------------------------------- (x+c)(1+p)=20 if c=5 , whatever p is , ( even is 0 ) x<=15 , but from the text , p can not be 0 , since there is tax payment ( or you will be fined ....kidding ) so B is sufficient but when p=6 or mean tax rate 6% x+c about 19 , x can be less or more than 15 ^^