average age

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average age

by Ankitaverma » Sun Nov 24, 2013 6:24 pm
Committee X and Committee Y , which have no common members, will combine to form Committee Z . Does Committee X have more members than Committee Y ?

(1) The average (arithmetic mean) age of the members of Committee X is 25.7 years and the average age of the members of Committee Y is 29.3 years.
2) The average (arithmetic mean) age of the members of Committee Z will be 26.6 years

Q/A-c why not e
Source: — Data Sufficiency |

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by Uva@90 » Sun Nov 24, 2013 7:28 pm
Ankitaverma wrote:Committee X and Committee Y , which have no common members, will combine to form Committee Z . Does Committee X have more members than Committee Y ?

(1) The average (arithmetic mean) age of the members of Committee X is 25.7 years and the average age of the members of Committee Y is 29.3 years.
2) The average (arithmetic mean) age of the members of Committee Z will be 26.6 years

Q/A-c why not e
Hi AnkitaVerma,
Given: Z= X+Y
To Find: X > Y

Let Ax be the Average age of Committee X
Ay be the Average age of Committee Y
AZ be the Average age of Committee Z

Statement1 : Ax = 25.7 and Ay = 29.3. It does not mention anything about the number of members.
Insufficient.

Statement 2:
Az = 26.6
Insufficient.

Combine 1 and 2:
we know that Committee Z is formed by combining X and Y

Ax(25.7) -----------------------------Ay(29.3)

Now place the Committee Z accordingly, Az = 26.6, Which comes closer to Ax than Ay.

Ax(25.7)-------Az(26.6)----------------Ay(29.3)
Hence Number of members in Committee X would be more than Y.

Answer is C

Regards,
Uva.
Known is a drop Unknown is an Ocean