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| Author: | Bunuel [ 05 Jul 2018, 23:15 ] |
| Post subject: | What is the value of (x - 1)(y + 1) ? (1) x + y = 4 (2) xy = 3 |
What is the value of (x - 1)(y + 1) ? (1) x + y = 4 (2) xy = 3 M36-130 |
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| Author: | Bunuel [ 16 Nov 2021, 08:26 ] |
| Post subject: | Re: What is the value of (x - 1)(y + 1) ? (1) x + y = 4 (2) xy = 3 |
Bunuel wrote: What is the value of (x - 1)(y + 1) ? (1) x + y = 4 (2) xy = 3 M36-130 Official Solution: What is the value of \((x - 1)(y + 1)\) ? (1) \(x + y = 4\) The above equation has infinitely many solutions for \(x\) and \(y\). Not sufficient. (2) \(xy = 3\) The above equation has infinitely many solutions for \(x\) and \(y\). Not sufficient. (1)+(2) From \(x + y = 4\) we can get that \(x=1\) and \(y=3\) or \(x=3\) and \(y=1\). For the first case, \((x - 1)(y + 1)=0\) but for the second case, \((x - 1)(y + 1)=6\). Not sufficient. Answer: E |
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| Author: | PKN [ 05 Jul 2018, 23:36 ] |
| Post subject: | Re: What is the value of (x - 1)(y + 1) ? (1) x + y = 4 (2) xy = 3 |
Bunuel wrote: What is the value of (x - 1)(y + 1) ? (1) x + y = 4 (2) xy = 3 Individually insufficient. combining, we have two values of both x and y for which (x - 1)(y + 1) will have two values. hence, insufficient. Ans (E) |
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| Author: | mygmat0101 [ 06 Jul 2018, 11:00 ] |
| Post subject: | Re: What is the value of (x - 1)(y + 1) ? (1) x + y = 4 (2) xy = 3 |
E individual statements are insufficient. we'll get two values of x and y x =1,3 y=3,1 so the binomial has 2 values so E |
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| Author: | Bunuel [ 24 Dec 2018, 00:38 ] |
| Post subject: | Re: What is the value of (x - 1)(y + 1) ? (1) x + y = 4 (2) xy = 3 |
Bunuel wrote: What is the value of (x - 1)(y + 1) ? (1) x + y = 4 (2) xy = 3 |
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| Author: | Archit3110 [ 24 Dec 2018, 02:09 ] |
| Post subject: | Re: What is the value of (x - 1)(y + 1) ? (1) x + y = 4 (2) xy = 3 |
Bunuel wrote: What is the value of (x - 1)(y + 1) ? (1) x + y = 4 (2) xy = 3 #1: x+y= 4 x,y can be (1,3) ( 2,2,) (4,0) insufficient #2 xy=3 3,1 , 1/3*9 ... in sufficient on combining we get (1,3 ) as the only number which would be sufficient .. IMO C answer is C over E so because definite values of x & y are not sure and we get two value s in (x - 1)(y + 1) on substitution of (3,1) or (1,3) |
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