collection of tough problems from G PREP - 18

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Over a certain time period, did the number of shares of stock in Ruth's portfolio increase?

1) Over the time period, the ratio of the number of shares of stock to the total number of shares of stocks and bonds in Ruth's portfolio increased.

2) Over the time period, the total number of shares of stock and bonds in Ruth's portfolio increased
Source: — Data Sufficiency |

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by harsh.champ » Sat Feb 06, 2010 6:12 am
abhasjha wrote:Over a certain time period, did the number of shares of stock in Ruth's portfolio increase?

1) Over the time period, the ratio of the number of shares of stock to the total number of shares of stocks and bonds in Ruth's portfolio increased.

2) Over the time period, the total number of shares of stock and bonds in Ruth's portfolio increased
IMO D.

The statements in itself are quite simple to solve the questions.

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by ajith » Sat Feb 06, 2010 8:48 am
abhasjha wrote:Over a certain time period, did the number of shares of stock in Ruth's portfolio increase?

1) Over the time period, the ratio of the number of shares of stock to the total number of shares of stocks and bonds in Ruth's portfolio increased.

2) Over the time period, the total number of shares of stock and bonds in Ruth's portfolio increased
1. insufficient - the increase may be because of buying shares of stocks or selling shares of bonds - not enough to conclude no of shares of stock increased
2. insufficient - The increase may be solely because of the purchase of new shares of bond or it could be because of the purchase of stock

1&2 combined is sufficient to conclude that no of shares of stocks increased in the portfolio
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by onedayi'll » Sun Feb 07, 2010 8:18 am
1) says S/(S+B) went up....

this is possible:
a.) if S goes up
b.) if B goes down...

So A is insufficient...

2.) S+B went up..
again...this can happen
a.) if S stay same and B goes up...
b.) is S and B both go up.then ratio increases

B is insufficient

Taking both together...b.) of 2 fits 1) and 2.) ...hence C

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