Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 350,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Re: What is the lowest positive integer that is divisible by [#permalink]
11 Sep 2012, 08:24

1

This post received KUDOS

Factors of 420 are: 1, 2, 2, 3, 5, 7

Now 420 should be divided by each of 1, 2, 3, 4, 5, 6, 7

From the factors which we get above by factorization and combining them to make all numbers from 1 to 7,

420 divided by 1 420 divided by 2 (picking up from factors) 420 divided by 3 (picking up from factors) 420 divided by 4 (picking up two 2s and multiplying to make it 4) 420 divided by 5 (picking up from factors) 420 divided by 6 (picking up 2 and 3 from factors and multiplying to make it 6) 420 divided by 7 (picking up from factors) All leaves remainder as ZERO.

No need to go further. Answer is A. _________________

Re: What is the lowest positive integer that is divisible by [#permalink]
11 Sep 2012, 09:07

1

This post received KUDOS

Here are the integers from 1 to 7 including: 1, 2, 3, 4, 5, 6, 7 So the lowest positive integer divisible by every single numbers set forth above would have to be divisible by 7,5,4,3 simultaneously or 7*5*4*3=420 please, correct me if I went awry _________________

What is the lowest positive integer that is divisible by each of the integers 1 through 7, inclusive? (A) 420 (B) 840 (C) 1,260 (D) 2,520 (E) 5,040

My choice is E.But its wrong. My Explanation:lowest positive integer that is divisible by each of the integers 1 through 7 means 7!. 7!=5040.Hence (E) However this answer is wrong. I am not able to understand the OG12 explanation

Re: What is the lowest positive integer that is divisible by [#permalink]
13 Jan 2013, 22:43

4

This post received KUDOS

You need LCM of first 7 numbers, NOT factorial. If a number is divisible by 6 then its also divisible by 2 & 3. You dont have to count 2 & 3 again when you consider factor as 6.

What is the lowest positive integer that is divisible by each of the integers 1 through 7, inclusive? (A) 420 (B) 840 (C) 1,260 (D) 2,520 (E) 5,040

My choice is E.But its wrong. My Explanation:lowest positive integer that is divisible by each of the integers 1 through 7 means 7!. 7!=5040.Hence (E) However this answer is wrong. I am not able to understand the OG12 explanation

Merging similar topics. Please ask if anything remains unclear.

P.S. Please read carefully and follow: rules-for-posting-please-read-this-before-posting-133935.html Pay attention to the rule #3: the name of a topic (subject field) MUST be the first 40 characters (~the first two sentences) of the question. _________________

Re: What is the lowest positive integer that is divisible by [#permalink]
17 Jan 2013, 02:58

PraPon wrote:

You need LCM of first 7 numbers, NOT factorial. If a number is divisible by 6 then its also divisible by 2 & 3. You dont have to count 2 & 3 again when you consider factor as 6.

Re: What is the lowest positive integer that is divisible by [#permalink]
17 Jan 2013, 08:31

the question stem says that the number is divisible by each of the integers from 1 through 7..then,simply,it means that each number is a factor of our lowest common multiple..hence 420 holds water

Re: What is the lowest positive integer that is divisible by [#permalink]
29 Dec 2013, 10:01

Bunuel wrote:

SOLUTION

What is the lowest positive integer that is divisible by each of the integers 1 through 7, inclusive?

(A) 420 (B) 840 (C) 1,260 (D) 2,520 (E) 5,040

The integer should be divisible by: 2, 3, 4(=2^2), 5, 6(=2*3), and 7. The least common multiple of these integers is LCM=2^2*3*5*7=420.

Answer: A.

Hi Bunuel,

I do understand the LCM but can you explain WHY when we have four sets of 2's we eliminate TWO of them?

For our two 3's, we eliminate one of them and I understand why - we might have the "same" 3. But when we eliminate two 2's, it's not as intuitive to me. Is it simply that, when we have an even number of the same integer, we remove half of them when we calculate the LCM? If so, what would've happened if we had three 2's or five 3's?

Re: What is the lowest positive integer that is divisible by [#permalink]
29 Dec 2013, 10:20

Expert's post

aeglorre wrote:

Bunuel wrote:

SOLUTION

What is the lowest positive integer that is divisible by each of the integers 1 through 7, inclusive?

(A) 420 (B) 840 (C) 1,260 (D) 2,520 (E) 5,040

The integer should be divisible by: 2, 3, 4(=2^2), 5, 6(=2*3), and 7. The least common multiple of these integers is LCM=2^2*3*5*7=420.

Answer: A.

Hi Bunuel,

I do understand the LCM but can you explain WHY when we have four sets of 2's we eliminate TWO of them?

For our two 3's, we eliminate one of them and I understand why - we might have the "same" 3. But when we eliminate two 2's, it's not as intuitive to me. Is it simply that, when we have an even number of the same integer, we remove half of them when we calculate the LCM? If so, what would've happened if we had three 2's or five 3's?

The lowest common multiple or lowest common multiple (lcm) or smallest common multiple of two integers a and b is the smallest positive integer that is a multiple both of a and of b.

To find the LCM, you will need to do prime-factorization. Then multiply all the factors (pick the highest power of the common factors). _________________

What is the lowest positive integer that is divisible by [#permalink]
24 Nov 2014, 12:46

Bunuel wrote:

What is the lowest positive integer that is divisible by each of the integers 1 through 7, inclusive?

(A) 420 (B) 840 (C) 1,260 (D) 2,520 (E) 5,040

Practice Questions Question: 40 Page: 157 Difficulty: 600

With this approach, if LCM of these numbers(from 1 to 7) was not available in options, than precious time could have been wasted while calculating LCM.

So in my opinion the quickest and most accurate approach would be to check the divisibility of each given option (by starting with lowest one) by using following rules:

3>>>>sum of digits should be divisible by 3 6>>>>integer should be divisible by both 2 and 3 9>>>>sum of digits should be divisible by 9 4>>>>should be divisible by 2 twice 5>>>>should be 0 or 5 in the end 7>>>>check divisibility in normal way

Please guide me if i am wrong?

gmatclubot

What is the lowest positive integer that is divisible by
[#permalink]
24 Nov 2014, 12:46

Hey, Last week I started a few new things in my life. That includes shifting from daily targets to weekly targets, 45 minutes of exercise including 15 minutes of yoga, making...

This week went in reviewing all the topics that I have covered in my previous study session. I reviewed all the notes that I have made and started reviewing the Quant...

I started running as a cross country team member since highshcool and what’s really awesome about running is that...you never get bored of it! I participated in...