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If n is a four-digit positive integer, then what is the tens

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If n is a four-digit positive integer, then what is the tens [#permalink]

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New post 15 Jun 2013, 08:02
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If n is a four-digit positive odd integer, then what is the tens digit of n?

1) the tens digit of n-9 is 0
2) the tens digit of n+9 is 2

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Re: If n is a four-digit positive integer, then what is the tens [#permalink]

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New post 15 Jun 2013, 08:11
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If n is a four-digit positive odd integer, then what is the tens digit of n?

1) the tens digit of n-9 is 0
N is in the range XX09 to XX18, but since it's odd the possible values are XX09,XX11,... till XX17
Not sufficient

2) the tens digit of n+9 is 2
N is in the range XX11 to XX20, but we are told that N is odd so the range is reduced: from XX11 to XX19.
The tens digit is always 1, sufficient
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Re: If n is a four-digit positive integer, then what is the tens [#permalink]

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New post 15 Jun 2013, 08:19
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Zarrolou wrote:
If n is a four-digit positive odd integer, then what is the tens digit of n?

1) the tens digit of n-9 is 0
N is in the range XX09 to XX18, but since it's odd the possible values are XX09,XX11,... till XX17
Not sufficient

2) the tens digit of n+9 is 2
N is in the range XX11 to XX20, but we are told that N is odd so the range is reduced: from XX11 to XX19.
The tens digit is always 1, sufficient


its given that the number is odd so the last digit can be 1,3,5,7 or 9 so there are few cases where we don't have to test the value :) but great explanation!
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Re: If n is a four-digit positive integer, then what is the tens [#permalink]

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New post 15 Jun 2013, 08:24
fozzzy wrote:
If n is a four-digit positive odd integer, then what is the tens digit of n?

1) the tens digit of n-9 is 0
2) the tens digit of n+9 is 2


From F.S 1 , for n = XX17,the tens digit of n-9 is 0,the tens digit of n is 1; for XX09,the tens digit of n-9 is 0, the tens digit of n is 0. Insufficient.

From F. S 2, we know that the units digit of n will atleast be 1(as n is odd). Thus, XXX1+9,gives tens digit of 2. Thus, the tens digit of n has to be 1.Sufficient.

B.
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Re: If n is a four-digit positive integer, then what is the tens [#permalink]

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New post 15 Jun 2013, 08:55
fozzzy wrote:
If n is a four-digit positive odd integer, then what is the tens digit of n?

1) the tens digit of n-9 is 0
2) the tens digit of n+9 is 2


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Hope it helps.
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Re: If n is a four-digit positive integer, then what is the tens [#permalink]

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New post 15 Jun 2013, 13:08
I completely missed that N was an odd integer... well played GMAT, well played.
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Re: If n is a four-digit positive integer, then what is the tens [#permalink]

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New post 09 Aug 2017, 09:49
Can someone please explain me the answer ?how is the range calculated?
Thanks
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Re: If n is a four-digit positive integer, then what is the tens [#permalink]

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New post 09 Aug 2017, 10:42
namrata88 wrote:
Can someone please explain me the answer ?how is the range calculated?
Thanks
Namrata


Quote:
If n is a four-digit positive odd integer, then what is the tens digit of n?

We are given that N is a Four Digit Integer.
N = ABCD
where A,B,C,D are representing the digits of the FOUR digit ODD number N.
We need the find a unique value for C = ?


Quote:
1) the tens digit of n-9 is 0

N = 1111
N - 9 = 1102
C = 1

But N = 1109
N - 9 = 1100
C = 0

2 different answer. Hence, the statement is Insufficient.


Quote:
2) the tens digit of n+9 is 2


N = ABCD = Odd
=> N = 1111
N + 9 = 1120
C = 2

N = 1119
N + 9 = 1128
C = 2

=> For the 4 digit odd integer, the value of the ten's digit denoted by C will always be 1.
B is sufficient, and is the answer.

Hope this helps!
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Re: If n is a four-digit positive integer, then what is the tens [#permalink]

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New post 09 Aug 2017, 10:49
1
namrata88 wrote:
Can someone please explain me the answer ?how is the range calculated?
Thanks
Namrata


Also, in terms of the range, you can try to use smaller numbers for the statements to understand what they mean.

For e.g.

Statement 1 - Ten's digit is 0 when N is subtracted by 9.

The maximum value of N can be 18, but since N is odd, the maximum value it can take is 17.
As 17 - 9 = 08
Here the ten's digit after subtraction is 0.
Minimum Value of N = 9
As 9 - 9 = 0 => Ten's digit will also be 0.

If we take N = 19, then N - 9 = 10
Here the ten's digit after subtraction is 1, and it breaks the statement. The statement is a fact, so this value is OUT of range.


Statement 2 - Ten's digit is 2 when 9 is added to N.
We cannot say N = 20, as N is odd.
So the maximum value of N = 19
And 19 + 9 = 28
The minimum value of N can be 11, as we need the ten's digit to be 2 when we add 9 to it.


Now try using this concept in a 4 digit odd number, and you'll figure it out.
Hope this helps.
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Re: If n is a four-digit positive integer, then what is the tens   [#permalink] 09 Aug 2017, 10:49
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