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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 (11266 reads) |
linical
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游客
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作者：游客 在 海归商务 发贴, 来自【海归网】 http://www.haiguinet.com
Let's look at two extreme cases first:
If we are extremely lucky and we win every single round of investment. To maximise return, we should invest 100% of the money every time for 100 times. Our return will be 2^100. Wow! a hugh number can make one the richest guy in the universe! However, this is 100% approach is extremely risky. Because the chance of winning 100 times in a row is 0.6^100. It is almost like zero and one single loss will wipe of all the investment.
On the other hand, suppose we are extremely unlucky and we will lose every time during the investment process. Of course, we want to invest 0% of our money. That is the best way to perserve the capital, though our gain is 0. Agian the chance of losing 100 times in a row is very slim too (0.4^100). To avoid risk, we are actually losing investment oppertunity here.
Base on these two extreme cases, we know neither should we invest all of the money nor should we invest none of the money every time. Instead, we should invest a portion of our money. Therefore, the risk of losing everything is avoided and meanwhile the oppertunity of gaining good return is still kept.
Now the question comes down to finding out the balancing point. In order to get maximum return, what percentage of of the mony should be invested every time?
Now, here is the assumption. If we invest 100 times, chances are we will win 60 times and lost 40 times. I would say this assumption is reasonable because 100 is a big enough number from statistic point of view. So our expected return should be:
(1-x)^40 X (1+x)^60
"x" is the percentage of the money invested very time. $2 investment cost in that included here.
The calculation result is: when x=0.2, we will get the maximun value of the equation which is 7.48987
So, Invest 20% of the money for 100 times. The expected retain is $7489.87
Done and Done!
BTW, Is the job still there?
作者：游客 在 海归商务 发贴, 来自【海归网】 http://www.haiguinet.com
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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 (11266 reads) - 搞不懂 -- pchf005 - (3 Byte) 2008-7-15 周二, 14:02 (235 reads)
- this question is not too difficult. just a math calculation. -- linical - (1928 Byte) 2005-9-22 周四, 23:41 (594 reads)
- 标准答案来了 -- ikonos - (332 Byte) 2005-8-16 周二, 16:02 (1348 reads)
- 标准答案 -- feebe - (253 Byte) 2005-8-15 周一, 21:02 (1313 reads)
- 瞧瞧这广告做的， -- 小报记者 - (24 Byte) 2005-8-15 周一, 21:56 (569 reads)
- 不一样 -- feebe - (0 Byte) 2005-8-16 周二, 00:32 (401 reads)
- 标准答案之一？ -- 坚强的肾 - (204 Byte) 2005-8-15 周一, 15:29 (515 reads)
- 函数 -- king - (398 Byte) 2005-8-15 周一, 12:39 (508 reads)
- 简单解法 -- Lycus - (245 Byte) 2005-8-15 周一, 11:43 (481 reads)
- 胡乱试一下。 -- pirate - (79 Byte) 2005-8-15 周一, 10:17 (393 reads)
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