What is the value of |y − 1| ?

Question

(1) (y − 7)(y + 5) = 0
(2) 2y + 10 = 0

Zarrolou · Answer

What is the value of |y − 1| ?

1) (y − 7)(y + 5) = 0 
y=7 or y=-5
 |y - 1|=|7 - 1|=6 
 |y - 1|=|- 5 - 1|=6 
Sufficient

2) 2y + 10 = 0 
y=-5
 |y - 1|=|- 5 - 1|=6 
Sufficient

IMO D

mau5 · Answer

From F.S 1, we have y=7 or y=-5. In any case, |y-1| = 6, Sufficient.

From F.S 2, we have a unique value for y, Sufficient.

D.

nt2010 · Answer

Answer is D

From Stmt 1, |y - 1| = 6 when y = 7 or -5.  -  Sufficient

From Stmt 2, |y - 1| = 6 when y = -5  -  Sufficient

//kudos please, if the above explanation is good.

tritringuyen · Answer

What is the value of |y − 1| ?

(1) (y − 7)(y + 5) = 0
(2) 2y + 10 = 0

For DS question, I think that we don't need to find value of y in (1) and (2).

(1). We have one equation with one variable y (exponent of 2), therefore we can find ly-1l => sufficient
(2). We have one equation and one variable y (exponent of 1). Similarly => sufficient.

D

This method is clearly relevant for complex questions.

mau5 · Answer

This question is designed in such a way that both the values of y are giving you the same value for |y-1|. Is not necessary that it will be the case all the time.

doe007 · Answer

You are right. There are similar questions where the absolute values for the two expressions are not the same.

Here this question is easy. But the questions set by GMAC often tests simple and basic concepts in a complicated way.

Bluelagoon · Answer

Tricky question. Watch out both the values -5 and 7 gives the same value of |y-1|.So A also qualifies. Hence D

doe007 · Answer

Your are right. With this type of setup, quadratic equations end up with same absolute value in some questions and different absolute values in some questions. Here the question is in a very simple form and can be solved very quickly (15-20 sec). Real GMAT questions may have more complicated form of the equation which will need more time to solve.

krrish · Answer

using both we can find out individually,

Trap in stmt1: we get 2 values but when we substuite final answer is same

email2vm · Answer

oh man! this one tricked me.

I just found the values individually 
1> y= 7 or y= -5 
2> y= -5

from 1 and 2 we have y =-5.....hence D....

But found that answer is C...have to complete the job before concluding...lesson learnt.

WoundedTiger · Answer

I think you interchanged the options.

If you combine 2 statements to get the answer then we choose option C
If both statements independently can give us the ans then we choose option D

Ans is D and not C for this Question

bumpbot · Answer

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What is the value of |y − 1| ?

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