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Integers ques...pls help!!

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Rocky Balboa
 Post subject: Integers ques...pls help!!
 Post Posted: Sun Jul 10, 2011 3:56 am 
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Students


Posts: 1
Please help understand if there is a better way to handle such questions..thanks in advance!

How many integers from 101 to 800, inclusive, remains the value unchanged when the digits were reversed?
(A) 50
(B) 60
(C) 70
(D) 80
(E) 90
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varun_783
 Post subject: Re: Integers ques...pls help!!
 Post Posted: Sun Jul 10, 2011 4:06 am 
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Course Students


Posts: 263
Hi,

What is the source of this question?

Thanks

Sunil
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adrielfrederick
 Post subject: Re: Integers ques...pls help!!
 Post Posted: Mon Jul 11, 2011 1:37 pm 
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The first and last digits should be the same for the value to not change.

i.e The three digit number should be in the format xyx

where x- can take values between 1 and 9 and y between 0 and 9

Therefore the answer would be 9 *10=90
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varun_783
 Post subject: Re: Integers ques...pls help!!
 Post Posted: Mon Jul 11, 2011 2:40 pm 
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Course Students


Posts: 263
Hi adrielfrederick,

The first and last digit cannot be between 1 and 9 as the range is between 101 and 800.

However, before we can answer this question we need to make sure that it is not from a banned source and that is why I have asked Deepti to specify it.

Thanks

Sunil
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jnelson0612
 Post subject: Re: Integers ques...pls help!!
 Post Posted: Mon Jul 25, 2011 1:01 pm 
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ManhattanGMAT Staff


Posts: 1857
Thanks Sunil. We do indeed need the source of this question.

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Jamie Nelson
ManhattanGMAT Instructor
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karthicramesh19
 Post subject: Re: Integers ques...pls help!!
 Post Posted: Tue Jul 26, 2011 12:31 pm 
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Students


Posts: 1
Hi,
Lets first consider digits from 101 to 200 inclusive.
The possible numbers in this range are 101,111,121,131,141,151,161,171,181, & 191. This makes a total of 10.
Similarly, 201 to 300, 301 to 400, 401 to 500, 501 to 600, 601 to 700 and 701 to 800 each have 10 numbers.
Therefore, that's a total of 10*7 = 70 numbers, hence Ans C.
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biswas_sandeep
 Post subject: Re: Integers ques...pls help!!
 Post Posted: Wed Jul 27, 2011 2:40 pm 
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Students


Posts: 8
I agree with Karthic's answer. It should be C --> 70.

Deepti can you pls confirm the correct answer.
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tim
 Post subject: Re: Integers ques...pls help!!
 Post Posted: Fri Aug 12, 2011 11:11 pm 
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ManhattanGMAT Staff


Posts: 2242
Location: Southwest Airlines, seat 21C
it looks like C is indeed correct..

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Tim Sanders
Manhattan GMAT Instructor
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