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If x is an integer, is x! + (x + 1) a prime number?
1) x < 10
2) x is even
  • a)
    Exactly one of the statements can answer the question
  • b)
    Both statements are required to answer the question
  • c)
    Each statement can answer the question individually
  • d)
    More information is required as the information provided is insufficient to answer the question
Correct answer is option 'D'. Can you explain this answer?
Verified Answer
If x is an integer, is x! + (x + 1) a prime number?1) x < 102) x is...
Stmt1 
x <10> x can be 2 so 2!+3 = 5 - prime 
But x can be 3 so 3!+4 = 10 - Non prime 
So InSuff 

Stmt2 
x is even. 

x can be 2 so 2!+3 = 5 - prime 
But x can be 14 so 14! + 15 is not prime 

Combine 1 and 2 you will see x! + x + 1 is prime

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Most Upvoted Answer
If x is an integer, is x! + (x + 1) a prime number?1) x < 102) x is...
Cannot be greater than 2.
2) x is a positive integer.

From statement 1, we know that x can only be 1 or 2. If x is 1, then x! (x-1) = 1! (1-1) = 0, which is not a prime number. If x is 2, then x! (x-1) = 2! (2-1) = 2, which is a prime number.

Therefore, statement 2 is not necessary and the answer is:

- If x = 1 or x > 2, the answer is NO.
- If x = 2, the answer is YES.
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Community Answer
If x is an integer, is x! + (x + 1) a prime number?1) x < 102) x is...
  • Statement 1 : Not Sufficient
  • 2! + (2+1) =2x1 + 3 = 5 (prime number)
  • 3! + (3+1) = 3x2x1 + 4 = 10 (not a prime number)
  • Statement 2 : Not Sufficient
  • 2! + (2+1) =2x1 + 3 = 5 (prime number)
  • 4! + (4+1) = 4x3x2x1+5 = 29 (prime number)
  • 6! + (6+1) = 6x5x4x3x2x1+7 = 727 (prime number)
  • 8! + (8+1) = 8x7x6x5x4x3x2x1 9 = 40329 (not a prime number)
  • Combined Statements 1 and 2 are not sufficient because when x<10 and x is even you get prime and non-prime numbers.
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If x is an integer, is x! + (x + 1) a prime number?1) x < 102) x is evena)Exactly one of the statements can answer the questionb)Both statements are required to answer the questionc)Each statement can answer the question individuallyd)More information is required as the information provided is insufficient to answer the questionCorrect answer is option 'D'. Can you explain this answer?
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If x is an integer, is x! + (x + 1) a prime number?1) x < 102) x is evena)Exactly one of the statements can answer the questionb)Both statements are required to answer the questionc)Each statement can answer the question individuallyd)More information is required as the information provided is insufficient to answer the questionCorrect answer is option 'D'. Can you explain this answer? for GMAT 2024 is part of GMAT preparation. The Question and answers have been prepared according to the GMAT exam syllabus. Information about If x is an integer, is x! + (x + 1) a prime number?1) x < 102) x is evena)Exactly one of the statements can answer the questionb)Both statements are required to answer the questionc)Each statement can answer the question individuallyd)More information is required as the information provided is insufficient to answer the questionCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for GMAT 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for If x is an integer, is x! + (x + 1) a prime number?1) x < 102) x is evena)Exactly one of the statements can answer the questionb)Both statements are required to answer the questionc)Each statement can answer the question individuallyd)More information is required as the information provided is insufficient to answer the questionCorrect answer is option 'D'. Can you explain this answer?.
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