If x equals the product of two consecutive single-digit prime numbers,

Question

If x equals the product of two consecutive single-digit prime numbers, which of the following is NOT the product of two consecutive integers?

A. 2x
B. 5x
C. 6x
D. 7x
E. 12x

EMPOWERgmatRichC · Answer

Hi All,

Since this question appears to be dropping down the page, I'm going to bump it up.

As a hint for how to solve it.... there are only a limited number of possible values that will fit the given description. Try listing them out - you'll likely get to the correct answer relatively quickly.

GMAT assassins aren't born, they're made,
Rich

Abhishek009 · Answer

There are only 4 Single digit prime numbers are - 2, 3 , 5 , 7

Lets check the options -

A. 2x - Possible numbers are 6 (2*3),10(2*5) & 14(2*7)
B. 5x - Possible numbers are 10(5*2),15(5*3) & 35(5*7)
C. 6x - Possible numbers is 6 ( 2*3 )
D. 7x - Possible Numbers are 14(7*2),21(7*3),35(7*5)
  E. 12x - Not Possible ; None of the multiples of 12 can be obtained using only 2 single digit prime numbers.

Mo2men · Answer

Dear Rich,
The single digit prime number is 2,3,5,7 But I'm really confused in the wording 'two consecutive single-digit numbers'. 2&3 are clearly conscetive prime but Can I consider 3 &5 or 5&7 are consecutive. I think so because no prime number between them.

Your clarification is highly appreciated to understand GMAT wording.

EMPOWERgmatRichC · Answer

Hi Mo2men,

GMAT questions are always carefully worded (otherwise you'd have trouble determining what your 'goal' was). While it's important to note the individual descriptive words in the prompt, you also have to think about how they relate to one another. The word 'consecutive' does mean 'in a row', but you have to pay attention to the other words too...

For example:

X equals the sum of 4 consecutive EVEN integers...

Can you come up with an example of what X could equal? X CANNOT equal 1+2+3+4, since those 4 integers are NOT all even (the words 'consecutive' AND 'even' must be noted).

In this prompt, we're told to deal with 2 consecutive one-digit PRIME numbers. Notice here that there are SEVERAL words/phrases to note: 'consecutive', 'one-digit' and 'primes.' Thus, the options are...

2 and 3
3 and 5
5 and 7

GMAT assassins aren't born, they're made,
Rich

Hnoorshn · Answer

1) 2x= 2* sum of consecutive prime number.
So 2 x (2x3) 
2x 6 = 12
Since 12 = 3*4 (two consequtive integers remove option 1)

2) 5x
5x (6) = 30
5 and 6 are consecutive so remove option 2

3) 6x 
6*6= 36 , no consecutive number
Lets try 3*5 (next two con prime numbers)
6*(3*5) = 90 
Or
90 = 9*10

4) 7 x 
Just like option (2) 7x = 7*6 consecutive numbers.

5) so it has to be option 5.

GMATinsight · Answer

Single Digit Prime Number = 2, 3, 5, 7

i.e. x may be 2*3 or 3*5 or 5*7
i.e. x may be 6 or 15 or 35

Checking Options

A. 2x  may be product of two consecutive Numbers for x = 6, 2x=12=3*4, Hence, INCORRECT OPTION 
B. 5x  may be product of two consecutive Numbers for x = 6, 5x=30=5*6, Hence, INCORRECT OPTION 
C. 6x  may be product of two consecutive Numbers for x = 15, 6x=90=9*10, Hence, INCORRECT OPTION 
D. 7x  may be product of two consecutive Numbers for x = 6, 7x=42=6*7, Hence, INCORRECT OPTION 
E. 12x  MUST BE CORRECT OPTION BUT SADLY IT IS'NT

@x=6, 12x = 12*6 = 72 = 8*9 hence INCORRECT

All Options are Incorrect

Mo2men · Answer

Dear GMATInsight,

When I check last option (E), I find for x =6, 12x=12*6=72= 8*9. Am I right? So option E should be incorrect.

I think the question is not worded accurately.

I believe that the source of the prompt meant to choose 2*3 because you can see that only option C, x= 15 but it seems that wording caused confusion.

Thanks

GMATinsight · Answer

You are so Right... I didn't even check 5th Option cause I could eliminate 4 options.

Swaroopdev · Answer

Hi Bunuel,

Is this question legitimate ? Because all the answer choices seem to be the product of consecutive integers, including the option C. Could you please clarify ?

Thanks.

If x equals the product of two consecutive single-digit prime numbers,

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