[原创]3.29 jj

zhliang2000

AA:

Management of recreation center saw the increase in the number of membership after the opening of new swimming pool. They conclude that more new facilities such as golf, multipurpose game center will boost the revenue further

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AI:

Which one should organization value more,     advices from outside expert or those from inside experienced employees.

    

Math:

A lot of jj in cd has appeared in the test. The only with some difficulties and without seen before is:

DS: One guy opened an account in two different banks with same amount of deposit. Bank X provides an annual interests rate x, compound quarterly. Bank Y provides one with annual interests y, compound semiannually. Is x > y?

1. After one year, both deposit receives same amount of interests
   
2. the combined interests received > 120

    

(1+x/4)^4 = (1+y/2)^2

(1+(8x+x^2)/16)^2 = (1+y/2)^2

8x+x^2 = 8y

8(y-x)=x^2>=0


Combine with 2, the choice is C

zhliang2000

HI, everyone.


I still think to answer is C. Because 8(y-x)=x^2 does not necessarily mean y-x > 0, it could mean x=y. So combined with 2, which means x > 0, then we can reach the conclusion y>x.


I think this is the trick of the question