GMAT score

[Queen09]

The GMAT is scored on a scale of 200 to 800 in 10 point increments. (Thus 410 and 760 are real GMAT scores but 412 and 765 are not). A first-year class at a certain business school consists of 478 students. Did any students of the same gender in the first-year class who were born in the same-named month have the same GMAT score?

(1) The range of GMAT scores in the first-year class is 600 to 780.

(2) 60% of the students in the first-year class are male.

[sanjeev_sharma]

From the question if the number of sutdent in class is greater than (800-200)/10 = 600/10 =60 then there are chances to have the 2 or more students having the same score. Here since the number of students is less i.e. 478, there are 478 - 60 = 418 students will be having the same score. Now only thing we want to number of female students in class.

Now, as statement A gives only the one thing we are able to know that there are 780-600 = 180/10 =18 i.e. there are 478 - 18 = 460 number of students on the same score. If the number of female student is 2 then it may be possible that obth the students are on different score. If the number of female student is greater than 18 then it is possible to have 2 female students at same score.

So it is not sufficient..

Now for the statement 2, we know that there are 478 * 60% = 191 female students in the class. Using this information and information in the question, we can similarly deduce that if the number of female students is > 60 then it is is true.

So the statement 2 alone is sufficient and theefore the answer is B.

[sandeepky]

I think its A.

According to 1 we can come to know that the score can have 19 values from 600 to 780.

Minimum no. of same gender students can be: 50% of 478= 239

So minimum number of students with similar score can be: 239/19 = 12.57 > 12

Which shows that at least 2 students wereborn in the same-named month

[sandeep_chads]

Given: If scores are between 200 and 800 then there are 60 scores possible. Assuming worst case, each kid is born in a different month so and different kids in the same month score different GMAT scores Therefore: 12*60 males and 12*60 ladies are possible720 males and 720 ladies can go without any repetition.

Option A If range = 600 - 780 then 18 scores possible. And the maximum again becomes 18*12= 216So if males = 217 and ladies = 217 then there has to be a repetitionIf total kids = 478 then minimum boys = 478/2 = 239 and so with ladies which is greater than 217 so it is sufficient

Option B Males = 227. Can't say. We need more than 712 of the same gender to prove the point so not sufficient

Official Answer please? imo = A

[manikdhingra]

m confused...can nyone explain in a easy way.....

[namitb]

Hi ,
The anser is A,

See the range is 600-780 which implies there are 19 possible values.

now , there are 12 months so there are 12*19 distinct values = 228

if the numer of any gender is >228 it will be a repetition.

the worst possible case is when of 478 the number of male and female is equal ....ie 239 thats why A is sufficient

if we dont have a given range then teh possible range of gmat scores is (800-200)/10 +1 61 so we can have 61*12 = 732 thus we need min 733 people of either gender to prove their there is a repetition

[bose]

it is A, total combinations possible=2*12*19=456. totals students=478, so some have to share combination

[manikdhingra]

what does 12*19 represents here

[Fiver]

My answer is A.

The total number of scores from 200 to 800 in increments of 10 could be :61 and since there 12 months the total possibilities are 61*12=732.
Now since the total number of students itself is less than the total possibilities i.e. 478<732, merely getting the number of same sexes cannot answer this question. This directly rules out B & D.

1=> given this range the total possibilities are 19*12=228. Here even if we have an equal ratio it still becomes 239 each, which ensures redundant cases.

Will wait to see the Official Answer.

[Queen09]

A is the Official Answer.

Well done all !