If m and n are positive integers such that m is a factor of

Question

If m and n are positive integers such that m is a factor of n, how many positive multiples of m are less than or equal to 2n ?

A. 2m/n + 1
B. 2n/m + 1
C. 2n/(m+1)
D. 2m/n 
E. 2n/m

KarishmaB · Accepted Answer

I don't think there is anything called 'the best approach'. Each person uses what works best for her/him. I jump to plugging in numbers whenever I see variables in the questions and variables in the options. I know that within 1 or 2 iterations, I should get my answer. I also like to choose the simplest possible numbers. e.g. here I would put m = 1 and n = 1 (both positive integers and m is a factor of n). But the moment I put them equal, I see that options d and e will be the same. So instead, I put m = 1 and n = 2. 2n = 4. 
Number of positive multiples of 1 that are less than or equal to 4 = 4 (1, 2, 3, 4)
Only e gives me 4 when I put n = 2 and m = 1
Answer (E).

Mind you, it is not a good idea to plug in numbers when you have 3-4 variables since you might just get lost in them.

144144 · Answer

Lets say N=10, M=5
2N=20. so the answer should be 4 (20/5)
lets try to plug in the answers:
A-not an integer
B-not an integer
C-not an integer
D-1 (not the answer)
E-4 - the answer. (the only one).

I would choose E.

Method 2
N=M*A (A is an integer)
So - A=N/M
therefore in 2N A will be 2N/M

Again - Answer is E.

Hope it helps.

*** personally - I love the mathematical approach. Easier for me, however, many people like the plug in numbers approach. It is important to master both methods so if one doesnt work, you can try the other.

144144 · Answer

Karishma, you are the greatest. +1

klankford · Answer

thank you for this!

arnoorichenna · Answer

In case of 3-4 variables good to use the table to track.

BDSunDevil · Answer

I think picking number is the best for this sort of problems.
i Picked m=3, n=12 
Only E worked.

OptimusPrimea1 · Answer

@karishma..

Same here i plugged in numbers too..m=2 and n=6..

IMO E..

prakhag · Answer

Plugging numbers seems like the best approach here.

1. Put n = 25 and m = 5
2. Put n = 4 and m = 2.

In both the scenarios only E stands out.

EUApplicant2014 · Answer

I think we can save some time here. It is a simple question asking the number of factors but in a twisted manner. For example, if I may ask how many positive multiples of 3 are less than or equal to 12 (6*2), given that 6 is multiple of 3. Its straight 12/3.

hdwnkr · Answer

Keyword: Positive
Lets say

m=4
n=16
2n=32

Every other option except for B and E give non integer values.

B indicates the answer to be 9. That would be true if we were to consider 0 as well. However, the question asks for positive.
0 is neither positive nor negative.

Hence, E

suramya26 · Answer

Since every one has given approach in which value is placed is the variable I have an approach without putting values..
Let me know if I am wrong...
m is a factor of n 
Therefore I can say
n= m*k where is the multiplying factor(For eg: if n=6 and m=3 then 6=3*2)
Hence  k=n/m ;
(2=6/3) Hence, we can say that  the number of multiples of n less than equal to m is equal to k (multiples of 3 less than equal to 6 are 2)
Similiarly, 
2m=n*k"
=> k"=2m/n

Hence, we can say that the number of multiples of n less than 2m equals to k" i.e.  2m/n ;

Actually in this question we are asked that by what factor 2m will be divided by n
 
FOCUS ON THE CONCEPT NOT THE QUESTION

Mo2men · Answer

Let m=2 & n=4 ...then m=2 & 2n=8

There are 4 multiples between 2 & 8 which are 2,4,6 & 8

A. 2m/n + 1 = 1 +1 = 2.......... Eliminate

B. 2n/m + 1 = 4 +1 =5............ Eliminate

C. 2n/(m+1) = 8/3.................. Eliminate

D. 2m/n = 4/4 =1 .................. Eliminate

Only choice left...we can check to be sure

E. 2n/m = 8/2 = 4.................. Keep

Answer: E

bumpbot · Answer

Automated notice from GMAT Club BumpBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.

If m and n are positive integers such that m is a factor of

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

If m and n are positive integers such that m is a factor of

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards