1. Good post? |

am i missing something?

If x and y are positive integers and y = sqrt(9 - x) , what is the value of y?
(1) x < 8
(2) y > 1

SPOILER: i marked E but the Official Answer is D

2. Good post? |
If x and y are positive integers and y = sqrt(9 - x) , what is the value of y?

=> x>0 and y>0

(1) x < 8
x=1,2,3,4,5,6,7 => y=sqrt(8), sqrt(7), sqrt(6), sqrt(5), sqrt(4), sqrt(3), sqrt(2)
but y is an integer
=> only y=sqrt(4)=2 is valid

sufficient

(2) y > 1
x=1,2,3,4,5,6,7,8 => y=sqrt(8), sqrt(7), sqrt(6), sqrt(5), sqrt(4), sqrt(3), sqrt(2), sqrt(1)

y is a positive integer and
y>1
=>y=2
sufficient

D

3. Good post? |
Skarya, thanks! I missed the fact that y must be an integer!!! This type of errors accounts for 90% of my mistakes....i'm so sad

4. Good post? |
Originally Posted by JustMe123
Skarya, thanks! I missed the fact that y must be an integer!! This type of errors accounts for 90% of my mistakes....i'm so sad

I have been making careless such mistakes sometimes - to improve - I always keep telling myself that Question stems contains vital information and should be looked at closely -

For variables - note if integers or not, +ve, -ve, otherwise must try
-2, -0.5, 0, +0.5, +2 etc. (key is I often used to miss the fractions!)

In DS - always do the condition 2 (so that no carry over of info from condition 1)

Always look for what break the given condition as that is what proves if information given is sufficient or not

5. Good post? |
I forgot 0 is neither positive or negative!!! God help me! D it is. y can only be 3.

6. Good post? |
Originally Posted by dshweta
I forgot 0 is neither positive or negative!! God help me! D it is. y can only be 3.
Shweta, y can only be sqrt(4)=2 NOT 3. Please check (I guess its typo).

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