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安氏大俗商业学:一道投资公司招聘资金管理人的面试题目 |
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安氏大俗商业学:一道投资公司招聘资金管理人的面试题目 -- 安普若 - (701 Byte) 2005-8-15 周一, 09:50 (11261 reads) |
halifax2008

头衔: 海归少校
加入时间: 2005/04/05 文章: 64
海归分: 13615
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作者:halifax2008 在 海归商务 发贴, 来自【海归网】 http://www.haiguinet.com
Assumptions:
1. all given conditions are true.
2. 100 investment opportunities are not overlapped. i.e. There is no more than one investment occuring at any given time.
Solution:
For the100 investments, we exactly know there must be 60 successful cases and 40 failed ones.
Let
Total --- all money in hand
Tcost --- transaction cost per investment ($2 in this case)
FailedCaseLeft --- possible failed cased ahead
So, in each of 100 investments, the amount of invested money should be
(Total - Tcost* (FailedCaseLeft + 1)) / (FailedCaseLeft + 1)
Example:
The first investment
Total = 1000
Tcost = 2
FailedCaseLeft = 40 (we know that 40 cases will be defauted in the future)
So, we invest
(1000 - 2*41)/41 = $ 22.3902439
The second investment
we have two cases now
1. The first investment is successful
Total = 1000 - $2 + $ 22.3902439 = 1020.3902439
Tcost = 2
FailedCaseLeft = 40 (The number of possible failed cases in the future doen't change since we won in the first investment)
So, we invest
(1020.3902439 - 2*41)/41
2. The first investment is failed
Total = 1000 - $2 - $ 22.3902439 = $ 975.6097561
Tcost = 2
FailedCaseLeft = 39 (The number of possible failed cases in the future is decreased by 1 since we lost in the first investment)
So, we invest
(975.6097561 - 2*40)/40
Following the same strategy to finish all 100 investments, we definitely will have positive return at the end. This is absolute profit.
My main concern is to be prepared for the worst case. So this is the reason why it needs to divide by (possible failed cased ahead + 1)
By the way, there is only theoretical maximum profit. It should be less than (very close to)
1000*2^60
It is mch greater than the sum of money in this world. hehe...
作者:halifax2008 在 海归商务 发贴, 来自【海归网】 http://www.haiguinet.com
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