Inequality Question........ Help

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Inequality Question........ Help

by swati.sug » Fri Jul 11, 2008 1:31 pm
Manhattan GMAT Inequalities Problem Set Q 5

If x>y ,and x<6> -3,what is the largest prime number that could be equal to x+y?

My answer :
x can be 0 1 2 3 4 5
y can be -2 -1 0 1 2 3 4 (as it is less that x)

So largest prime no is 5+2 =7
But this is wrong according to solution
Please help...

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Re: Inequality Question........ Help

by lunarpower » Fri Jul 11, 2008 8:42 pm
hey.

when you post problems like this one, with "<" and ">" signs, you have to disable HTML. otherwise, the forum will "think" that the inequality signs are actually html tags, and will interpret them accordingly - an action that includes ignoring all the text between a "<" and a ">" if it doesn't constitute a valid html tag.

therefore, large swaths of your text are disappearing from the problem.

to fix this: check the Disable HTML in this post box underneath the text when you're posting.
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by johnybravo » Fri Jul 11, 2008 11:56 pm
And what is the answer in the solution
i think 3 is the answer
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by swati.sug » Sat Jul 12, 2008 12:13 pm
Ok I have disabled HTML..Ques is
Manhattan GMAT Inequalities Problem Set Q 5

If x>y ,and x<6 and y> -3,what is the largest prime number that could be equal to x+y?

My answer :
x can be 0 1 2 3 4 5
y can be -2 -1 0 1 2 3 4 (as it is less that x)

So largest prime no is 5+2 =7
But this is wrong according to solution
Please help...

Answer is not 3...
Please explain why u said 7 is wrong..
Last edited by swati.sug on Sat Jul 12, 2008 12:17 pm, edited 1 time in total.

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by swati.sug » Sat Jul 12, 2008 12:16 pm
Ans in manhattan gmat says:

Max value for x is 6 and since x>y max value for y is 6.
thus x + y can have max value 12.

The largest prime no less than 12 is 11 . Thus answer is 11.

Is this right approach for such questions?

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by tzink » Sat Jul 12, 2008 1:18 pm
swati.sug wrote:Ans in manhattan gmat says:

Max value for x is 6 and since x>y max value for y is 6.
thus x + y can have max value 12.

The largest prime no less than 12 is 11 . Thus answer is 11.

Is this right approach for such questions?
Does the problem state that x<6 or x<=6? as in, less than, or less than or equal to? because if it's 'less than', then the manhattan gmat answer doesn't make sense. the max value for x would be 5 (assuming x belongs to I).

It seems to me that the answer should be 7 as well, since the max value for x is 5, and the max value for y is 4. 5+4=9. largest prime under 9 is 7.

Unless, of course, x and y are not integers. if x=5.9 and y=5.1, then x+y would be 11...

any thoughts?

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by swati.sug » Sat Jul 12, 2008 11:31 pm
Yes it says less than and not less than or equal to.
I think the answer is wrong then..

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by sudhir3127 » Sun Jul 13, 2008 3:14 am
Even i think Manhattan answer is wrong if its just greater than and not(>=)..
My answer is also 3.

X can take values from - infinity to positive 5.

Y can take values from -2 to positive infinity.

but since X>Y

X can take values, 5,4,3,2,1,0

and y can take only -2 and -1 ( as -1 is smaller than 0)

so the prime number will be 5 +(-2) = 3


let me know if my understanding is right.

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by Ian Stewart » Sun Jul 13, 2008 8:25 am
tzink has the right idea above- the question doesn't tell you that x and y are integers. So, x could be 5.6 and y could be 5.4, and x+y could be 11.