Have questions about your preparation or an upcoming test? Need help modifying the Study Plan to meet your unique needs? No problem. Just book a Skype meeting with Brent to discuss these and any other questions you may have.

- Video Course
- Video Course Overview - READ FIRST
- General GMAT Strategies - 7 videos (all free)
- Data Sufficiency - 16 videos (all free)
- Arithmetic - 38 videos (some free)
- Powers and Roots - 36 videos (some free)
- Algebra and Equation Solving - 73 videos (some free)
- Word Problems - 48 videos (some free)
- Geometry - 42 videos (some free)
- Integer Properties - 38 videos (some free)
- Statistics - 20 videos (some free)
- Counting - 27 videos (some free)
- Probability - 23 videos (some free)
- Analytical Writing Assessment - 5 videos (all free)
- Reading Comprehension - 10 videos (all free)
- Critical Reasoning - 38 videos (some free)
- Sentence Correction - 70 videos (some free)
- Integrated Reasoning - 17 videos (some free)

- Study Guide
- Office Hours
- Extras
- Guarantees
- Prices

## Comment on

Divisor Rules## Hello Brent,

In the link below

https://gmatclub.com/forum/is-a-multiple-of-139044.html

You wrote " Given: If the average (arithmetic mean) the 4 numbers is 30 "

How did u come to this inference from Question stem

Regards,

Abhimanyu

## Good catch. When I answer

Good catch. When I answer Data Sufficiency questions, I paste in a pre-formatted template, and that template has that information about the average. I forgot to delete that part of my template.

I have since edited my response. Thanks!

## Hello Brent,

Need one clarification.

When we say if x is a divisor of m and n both means m/x, n/x then ( m+n)/x or ( m-n)/x.

Then in the below example why it can't be true

that when (2k-4) is divisible by 7 then 2k/7 and 4/7 is possible.

Regards,

Abhimanyu

## We need to be careful here.

We need to be careful here. This is an IF-THEN construction.

So, for example, IF x is a divisor of m and n, THEN x is a divisor of m+n, and x is a divisor of m-n. For example, since 5 is a divisor of 25 and 15, we know that 5 is a divisor of 25+15 and 25-15.

We can't necessary reverse that order though.

For example, even though 3 is a divisor of 5+4, we can't conclude that 3 is a divisor of 5 and 3 is a divisor of 4.

## Hello Brent, thanks for your

## Hi fobembe,

Hi fobembe,

Those values (47, 98, etc) are arbitrary numbers; they could be ANY integers.

For example, if 5 is a divisor of 35, then 5 must be a divisor of ANY product of 35 and some other integer. So, 5 must be a divisor of the following products:

(35)(11)

(35)(6587)

(35)(-29)

(35)(789,006)

etc.

Likewise, since 13 is a divisor of 39, then we know that 13 must be a divisor of ANY product of 39 and some other integer. So, 13 must be a divisor of the following products:

(39)(8)

(39)(734)

(39)(18,211)

(39)(-41)

etc.

Does that help?

## Can you someone help me with

If x is an integer and y = 3x + 2, which of the following CANNOT be a divisor of y?

A. 4

B. 5

C. 6

D. 7

E. 8

## APPROACH #1

APPROACH #1

Test various possible values of x and y

If x = 1, then y = 5.

So, 5 CAN be a divisor of y

ELIMINATE B

If x = 2, then y = 8.

So, 4 CAN be a divisor of y, and 8 CAN be a divisor of y

ELIMINATE A and E

If x = 3, then y = 11.

If x = 4, then y = 14.

So, 7 CAN be a divisor of y

ELIMINATE D

By the process of elimination, the correct answer is C

------------------------------------

APPROACH #2

For a number to be divisible by 6, the number must by divisible by 2 AND by 3

The question tells us that y = 3x + 2

In other words, y is TWO GREATER than some multiple of 3

In other words, y is NOT divisible by 3

If y is NOT divisible by 3, then y is NOT divisible by 6

Answer: C

## If x is an integer and y=3x+2

A) 4

B) 5

C) 6

D) 7

E) 8

if X = 1 Y = 5

In my opinion 4 (A) is not a divisor of 5, hence the correct answer is C??

Could you maybe explain what I am missing here?

## Yes, the correct answer is C.

Yes, the correct answer is C.

When x = 1, y = 5

Since 5 IS a divisor of 5, we can ELIMINATE B

When x = 2, y = 8

Since 4 and 8 are both divisors of 8, we can ELIMINATE A and E

Keep going to get C as the final answer.

Here's my full solution: https://gmatclub.com/forum/if-x-is-an-integer-and-y-3x-2-which-of-the-fo...

## Hi Brent, failing to

## This is a Strange Operator

This is a Strange Operator question, which is covered here: https://www.gmatprepnow.com/module/gmat-algebra-and-equation-solving/vid...

GIVEN: [n denotes the product of all the integers from 1 to n, inclusive.

So the "[" symbol tells us to do something to the value next to it.

For example: [6 = the product of all the integers from 1 to 6, inclusive.

That is, [6 = (1)(2)(3)(4)(5)(6)

Likewise: [8 = the product of all the integers from 1 to 8, inclusive.

That is, [8 = (1)(2)(3)(4)(5)(6)(7)(8)

The question asks "How many prime numbers are there between [6 + 2 and [6 + 6, inclusive?"

In other words, "How many prime numbers are there between (1)(2)(3)(4)(5)(6) + 2 and (1)(2)(3)(4)(5)(6) + 6?"

Does that help?

Cheers,

Brent

## https://gmatclub.com/forum/a

please explain

## Here's my solution: https:/

Here's my solution: https://gmatclub.com/forum/a-b-and-c-are-positive-integers-if-a-b-and-c-...

Cheers,

Brent

## Hi Brent, does the reverse

## No, the reverse does not hold

No, the reverse does not hold true in this case.

For example, 5 is a divisor of (7 + 3), but 5 is NOT a divisor of either 7 or 3.

Cheers,

Brent

## Add a comment