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If a 3-digit integer is selected at random from the

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If a 3-digit integer is selected at random from the  [#permalink]

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New post 11 Nov 2007, 15:29
1
3
00:00
A
B
C
D
E

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(N/A)

Question Stats:

85% (01:10) correct 15% (00:53) wrong based on 226 sessions

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If a 3-digit integer is selected at random from the
integers 100 through 199, inclusive, what is the
probability that the first digit and the last digit of the
integer are each equal to one more than the middle
digit?

(A) 2/225

(B) 1/111

(C) 1/110

(D) 1/100

(E) 1/50
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 [#permalink]

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New post 11 Nov 2007, 16:15
eyunni wrote:
(C).1/100.

(101)


wah, i got where i made mistake.

199-100+1=200
and got
1/200

rather than 100

thxz!
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 [#permalink]

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New post 12 Nov 2007, 13:17
I'm confused :?

I've got 10 possible numbers
100 1+0 is 1 greater than 0
111 1+1 is 1 greater than 1
122 1+2 is 1 greater than 2
133 ....etc
144
155
166
177
188
199

That gives 10/100. What am I missing???
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 [#permalink]

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New post 12 Nov 2007, 13:22
gixxer1000 wrote:
I'm confused :?

I've got 10 possible numbers
100 1+0 is 1 greater than 0
111 1+1 is 1 greater than 1
122 1+2 is 1 greater than 2
133 ....etc
144
155
166
177
188
199

That gives 10/100. What am I missing???


Here we go...

If a 3-digit integer is selected at random from the
integers 100 through 199, inclusive, what is the
probability that the first digit and the last digit of the
integer are each equal to one more than the middle
digit
?

only possible number is 101

1/100
Director
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Posts: 520
Schools: Stern, McCombs, Marshall, Wharton
 [#permalink]

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New post 12 Nov 2007, 13:31
I see now, I thought it meant to add the first and last digit. :oops:
Manager
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Re: simple probability [#permalink]

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New post 28 Sep 2009, 10:35
The only number between 100 and 199 that satisfies this condition is 101.

Probability = 1/100
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Re: If a 3-digit integer is selected at random from the [#permalink]

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New post 10 Jan 2012, 09:53
+1 D

The number is 101. So, the probability is 1/100.
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Re: If a 3-digit integer is selected at random from the [#permalink]

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New post 10 Jan 2012, 21:32
Ans is 1/100

only 1 number satisfies the above mentioned condition i.e. 101.
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Re: If a 3-digit integer is selected at random from the [#permalink]

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New post 10 Jan 2012, 23:36
1
the required number is 101 (one number)
total of numbers=199-100+1=100
1/100
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Re: If a 3-digit integer is selected at random from the [#permalink]

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New post 31 Mar 2018, 09:45
Hi ALL,

The question uses the phrase "the first digit and the last digit of the integer are EACH EQUAL to "ONE MORE" than the middle digit." This means that the first and third digits are the SAME digit and that each is ONE MORE than the second digit.

Given the range that we have to work with (101 - 199), the ONLY number that fits this description is "101."

Since there are 100 total numbers in that range, the probability is 1/100

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Re: If a 3-digit integer is selected at random from the   [#permalink] 31 Mar 2018, 09:45
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