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Bunuel
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If x is a prime number, what is the value of x? 21 Aug 2023, 01:30
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55% (hard)

Question Stats:

53% (01:08) correct 47% (01:09) wrong based on 138 sessions

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If x is a prime number, what is the value of x?

(1) There are 3 prime numbers between 11 and x, not inclusive.
(2) x + 1 is a prime number.


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B
Pure algebraic questions like this one are no longer part of the GMAT Data Sufficiency syllabus.
For relevant Data Sufficiency questions, please check the Data Sufficiency forum:
Data Sufficiency Forum
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If x is a prime number, what is the value of x? Updated on: 21 Aug 2023, 03:08
Originally posted by Nabneet on 21 Aug 2023, 02:01.
Last edited by Nabneet on 21 Aug 2023, 03:08, edited 1 time in total.
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If x is a prime number, what is the value of x?

(1) There are 3 prime numbers between 11 and x, not inclusive.
(2) x + 1 is a prime number.


St1:
2,3,5,7,11
11,13,17,19,20
So, x can be 2 or 20 . Not Sufficient

St2:
x=2, x+1=3
Sufficient



IMO: Answer B
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If x is a prime number, what is the value of x? 21 Aug 2023, 02:36
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Nabneet
If x is a prime number, what is the value of x?

(1) There are 3 prime numbers between 11 and x, not inclusive.
(2) x + 1 is a prime number.


St1:
2,3,5,7,11
11,13,17,19,20
So, x can be 2 or 20 . Not Sufficient

St2:
x=2, x+1=3
x=4, x+1=5
Not Sufficient

St1 & St2:
Only 2(x),3,5,7,11 possible.

IMO: Answer C
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Answer is B as X has to be prime itself and 4 is not a prime. X has to be 2 so 2+1 is 3 which is a prime itself
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If x is a prime number, what is the value of x? 21 Aug 2023, 03:09
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Its_me_aka_ak
Nabneet
If x is a prime number, what is the value of x?

(1) There are 3 prime numbers between 11 and x, not inclusive.
(2) x + 1 is a prime number.


St1:
2,3,5,7,11
11,13,17,19,20
So, x can be 2 or 20 . Not Sufficient

St2:
x=2, x+1=3
x=4, x+1=5
Not Sufficient

St1 & St2:
Only 2(x),3,5,7,11 possible.

IMO: Answer C

Answer is B as X has to be prime itself and 4 is not a prime. X has to be 2 so 2+1 is 3 which is a prime itself
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Sorry Its_me_aka_ak,
my bad, missed the given info that x is prime.
Edited my response.
Thank You.
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If x is a prime number, what is the value of x? 18 Dec 2024, 07:24
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have a question on statement 1. if x is a prime number and not inclusive of the 3 prime numbers in between 11 and x, then the 4 prime numbers after 11 would be: 11, 13, 17, 19, 23. so would the answer for statement 1 not be 23 ? so statement 1 would also be sufficient ?
Nabneet
If x is a prime number, what is the value of x?

(1) There are 3 prime numbers between 11 and x, not inclusive.
(2) x + 1 is a prime number.


St1:
2,3,5,7,11
11,13,17,19,20
So, x can be 2 or 20 . Not Sufficient

St2:
x=2, x+1=3
Sufficient



IMO: Answer B
Show more
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Bunuel
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If x is a prime number, what is the value of x? 18 Dec 2024, 07:35
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tejy123
have a question on statement 1. if x is a prime number and not inclusive of the 3 prime numbers in between 11 and x, then the 4 prime numbers after 11 would be: 11, 13, 17, 19, 23. so would the answer for statement 1 not be 23 ? so statement 1 would also be sufficient ?
Nabneet
If x is a prime number, what is the value of x?

(1) There are 3 prime numbers between 11 and x, not inclusive.
(2) x + 1 is a prime number.


St1:
2,3,5,7,11
11,13,17,19,20
So, x can be 2 or 20 . Not Sufficient

St2:
x=2, x+1=3
Sufficient



IMO: Answer B
Show more

What if x is 2? There are three primes between 2 and 11.
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If x is a prime number, what is the value of x? 18 Dec 2024, 07:39
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ahh, that makes a lot of sense. Did not think about if X was less than 11. got it, thank you Bunuel!
Bunuel
tejy123
have a question on statement 1. if x is a prime number and not inclusive of the 3 prime numbers in between 11 and x, then the 4 prime numbers after 11 would be: 11, 13, 17, 19, 23. so would the answer for statement 1 not be 23 ? so statement 1 would also be sufficient ?
Nabneet
If x is a prime number, what is the value of x?

(1) There are 3 prime numbers between 11 and x, not inclusive.
(2) x + 1 is a prime number.


St1:
2,3,5,7,11
11,13,17,19,20
So, x can be 2 or 20 . Not Sufficient

St2:
x=2, x+1=3
Sufficient



IMO: Answer B

What if x is 2? There are three primes between 2 and 11.
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If x is a prime number, what is the value of x? 22 Dec 2024, 08:48
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If x is a prime number, what is the value of x?

(1) There are 3 prime numbers between 11 and x, not inclusive.
(2) x + 1 is a prime number.

1)it is not mentioned if x is less than or greater than 11
if x<11
7,5,3,2

if x>11
13,17,19, 23

Two possible answers, therefore 1 alone is Not sufficient

2) there is only one such case where two consecutive numbers are prime numbers:- 2 and 3
thus, x=2
x+1-3
B) 2 alone is sufficient
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