DS Problem

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Source: — Data Sufficiency |

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by pemdas » Thu Jan 26, 2012 6:11 pm
st(1) doesn't speak about x, Insuff
st(2) 3x+2y<10, Can be 3x<2(5-y) OR x<(2/3)*(5-y). Both must fill in positive integers. and y can be 1,2,3 to leave positive integer for x. Then x can be 1 or 2. Insuff
combining st(1&2): y>=3 then x can be ONLY 1. Suff

c
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by Anurag@Gurome » Thu Jan 26, 2012 7:37 pm
knight247 wrote:No OA on this one
(1) y ≥ 3 does not give any info about x; NOT sufficient.

(2) 3x + 2y < 10
If x = 1, y = 1, then 3x + 2y = 5 < 10; here value of x = 1
If x = 2, y = 1, then 3x + 2y = 8 < 10; here value of x = 2
No definite answer; NOT sufficient.

Combining (1) and (2), y ≥ 3 and 3x + 2y < 10
If y = 3 (the minimum possible value of y), and x = 1, then 3x + 2y = 3 + 6 = 9 < 10
If y = 3, and x = 2, then 3x + 2y = (3 * 2) + 6 = 12 > 10
So, the only possible value of x = 1; SUFFICIENT.

The correct answer is C.
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by tpr-becky » Tue Jan 31, 2012 10:30 am
Statement 1 gives no info about x - Not Sufficient

Statemetn 2 gives some info - pick some numbers and you find that x=1 y=1 works but so does x=2 y=2 so this is Insufficient as well.

Put them together and now you can sovle that 3x<10-2(3) so 3x<4 - thus x < 4/3. x still must be a positive integer so x must = 1. Sufficient and the answer is C.
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