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.

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:

Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

Re: If a, b and x are integers greater than zero, then which of the follow
[#permalink]

Show Tags

17 Sep 2018, 08:50

2

Top Contributor

3

Bunuel wrote:

If a, b and x are integers greater than zero, then which of the following must be greater than \(\frac{a}{a+b}\)?

(A) \(\frac{a+x}{a+b+x}\)

(B) \(\frac{a-x}{a+b+x}\)

(C) \(\frac{2a}{2a+2b+x}\)

(D) \((\frac{a}{a+b})^{2}\)

(E) \(\frac{a-1}{a+b-1}\)

--------ASIDE--------------------------------------- Here's a nice property of fractions: If a, b and k are positive, then (a + k)/(b + k) approaches 1 as k gets bigger. For example, the fraction (2+11)/(3+11) is closer to 1 than 2/3 is. Likewise, the fraction (1+7)/(2+7) is closer to 1 than 1/2 is. -----ONTO THE QUESTION!!!-------------------------------------

Since a and b are positive, we know that a+b > a So, the fraction a/(a+b) must be less than 1

So, based on the above property, if we add a positive number to numerator and denominator, the resulting fraction will be closer to 1 than the original fraction is.

Check the answer choices. . . . (A) (a + x)/(a + b + x) Since x is positive, we know that (a + x)/(a + b + x) will be closer to 1 than a/(a+b) is. Since a/(a+b) is less than 1, we know that (a + x)/(a + b + x) will be greater than a/(a+b)

Re: If a, b and x are integers greater than zero, then which of the follow
[#permalink]

Show Tags

19 Sep 2018, 21:30

pandeyashwin wrote:

Assume the value 1 each. Ans A

Can you please clarify, how did you know to assume the value 1 for each? Is this a rule somewhere? Or some sort of pre-thinking that I am not aware of? Thanks!

If a, b and x are integers greater than zero, then which of the follow
[#permalink]

Show Tags

19 Sep 2018, 22:16

1

sarahfiqbal wrote:

pandeyashwin wrote:

Assume the value 1 each. Ans A

Can you please clarify, how did you know to assume the value 1 for each? Is this a rule somewhere? Or some sort of pre-thinking that I am not aware of? Thanks!

The condition for this question is : a , b, x > 0 & they are integers.

Therefore we are free to assume any values we like as long as it follows the given condition.

I assumed 1 each because it's the easiest one to calculate. But if you get more than 1 correct option with your assumption, you should assume different set of values such as a = 1 , b= 2 ,c = 3 to rule out the wrong choices.

Re: If a, b and x are integers greater than zero, then which of the follow
[#permalink]

Show Tags

20 Sep 2018, 03:20

1

1

Bunuel wrote:

If a, b and x are integers greater than zero, then which of the following must be greater than \(\frac{a}{a+b}\)?

(A) \(\frac{a+x}{a+b+x}\)

(B) \(\frac{a-x}{a+b+x}\)

(C) \(\frac{2a}{2a+2b+x}\)

(D) \((\frac{a}{a+b})^{2}\)

(E) \(\frac{a-1}{a+b-1}\)

It's a basic concept that if x/y < 1 then (x+a)/(y+a) > x/y because same number added in numerator and denominator increases numerator by greater percentage than the percentage that it increases the denomenator

Hence, Answer Option A
_________________

Prosper!!! GMATinsight Bhoopendra Singh and Dr.Sushma Jha e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772 Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi http://www.GMATinsight.com/testimonials.html

Re: If a, b and x are integers greater than zero, then which of the follow
[#permalink]

Show Tags

07 Oct 2018, 21:24

sarahfiqbal wrote:

pandeyashwin wrote:

Assume the value 1 each. Ans A

Can you please clarify, how did you know to assume the value 1 for each? Is this a rule somewhere? Or some sort of pre-thinking that I am not aware of? Thanks!

Rather than assuming one for each term, know that a fundamental rule of fractions is that adding the same number to both numerator and denominator brings the fraction closer to that number.

So, adding x to both numerator and denominator brings the fraction closer to x. The value of x doesn't matter. Since we know it's an integer (1 or greater) and a/a+b is a fraction, adding x will bring the fraction closer to x, therefore, increasing it.
_________________

The importance of mindset on the GMAT - 640 to 690 to 740 (Q49 V42) : https://bit.ly/2R1WaK5

gmatclubot

Re: If a, b and x are integers greater than zero, then which of the follow &nbs
[#permalink]
07 Oct 2018, 21:24