GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 21 Sep 2019, 00:26 ### GMAT Club Daily Prep

#### 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

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. ### Request Expert Reply # What is the value of (8a + a - b)/(a - b) ? (1) (5a + 4b)/(a - b) = 2

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Math Expert V
Joined: 02 Sep 2009
Posts: 58142
What is the value of (8a + a - b)/(a - b) ? (1) (5a + 4b)/(a - b) = 2  [#permalink]

### Show Tags 00:00

Difficulty:   55% (hard)

Question Stats: 61% (01:44) correct 39% (02:12) wrong based on 99 sessions

### HideShow timer Statistics

What is the value of $$\frac{(8a + a - b)}{(a - b)}$$ ?

(1) $$\frac{(5a + 4b)}{(a - b)} = 2$$

(2) $$a - b = 9$$

Source: GmatFree

_________________
Retired Moderator D
Joined: 30 Jan 2015
Posts: 801
Location: India
Concentration: Operations, Marketing
GPA: 3.5
Re: What is the value of (8a + a - b)/(a - b) ? (1) (5a + 4b)/(a - b) = 2  [#permalink]

### Show Tags

(8a+a−b) / (a−b)
(9a-b) /(a-b) Dividing both numerator and denominator by b, we get:
(9a/b - 1) / (a/b-1) ----> (A)

(1) (5a+4b) / (a−b)=2 (solving, we get)
3a-2b = 0
3a = 2b
a/b = 2/3
Now, putting the value of a/b in equation A the final value can be obtained, Sufficient.

(2) a−b = 9
putting b = a+9 in equation A we get 8a + 9 (not solvable), Insufficient

Hence, A.
_________________
The few, the fearless !

Thanks Senior Manager  D
Joined: 18 Jun 2018
Posts: 267
Re: What is the value of (8a + a - b)/(a - b) ? (1) (5a + 4b)/(a - b) = 2  [#permalink]

### Show Tags

OA: A
$$\frac{(8a+a−b)}{(a−b)}$$ can be simplified as $$\frac{8a}{a-b}+1$$
$$\frac{8a}{a-b}+1$$ = $$\frac{8}{(1- \frac{b}{a})}+1$$
So we have to find value of $$\frac{b}{a}$$

1) $$\frac{(5a+4b)}{(a−b)}=2$$
if we take $$a=0$$ ,$$L.H.S\neq{R.H.S}$$, so it means $$a\neq{0}$$
Dividing numerator and denominator of $$L.H.S$$ by $$a$$ , we get
$$\frac{(5+4*\frac{b}{a})}{(1−\frac{b}{a})}=2$$
Solving above equation , we can find value of $$\frac{b}{a}$$
So Statement 1 alone is sufficient.

2) $$a−b = 9$$
Putting $$a-b$$ in $$\frac{8a}{a-b}+1$$ , we get $$\frac{8a}{9}+1$$
We still need value of $$a$$.
So Statement 2 alone is not sufficient.
Senior Manager  P
Joined: 20 Mar 2018
Posts: 331
Location: Ghana
Concentration: Finance, Real Estate
What is the value of (8a + a - b)/(a - b) ? (1) (5a + 4b)/(a - b) = 2  [#permalink]

### Show Tags

So (2) looks simple ,not sufficient as we have extra “a” in the numerator
(1) Gives a linear equation which we can derive a relationship between a and b ,so sufficient

Posted from my mobile device

Originally posted by Staphyk on 21 Aug 2019, 03:51.
Last edited by Staphyk on 21 Aug 2019, 04:12, edited 1 time in total.
Intern  B
Joined: 04 Nov 2015
Posts: 44
Re: What is the value of (8a + a - b)/(a - b) ? (1) (5a + 4b)/(a - b) = 2  [#permalink]

### Show Tags

Staphyk wrote:
So (2) looks simple ,not sufficient as we have extra “a” in the numerator
(1) Gives is one linear equation
(1+2) Gives two systems of equations hence value can be found

Answer C Posted from my mobile device

Answer will be option A.
If we solve the option A we will get a = -2b.
substituting this value in the main equation will yield a value of 19/3.
Hence the we are able to get a definite value from option A which will be the answer.
Senior Manager  P
Joined: 20 Mar 2018
Posts: 331
Location: Ghana
Concentration: Finance, Real Estate
Re: What is the value of (8a + a - b)/(a - b) ? (1) (5a + 4b)/(a - b) = 2  [#permalink]

### Show Tags

Lolx was not even solving
sandeep211986 wrote:
Staphyk wrote:
So (2) looks simple ,not sufficient as we have extra “a” in the numerator
(1) Gives is one linear equation
(1+2) Gives two systems of equations hence value can be found

Answer C Posted from my mobile device

Answer will be option A.
If we solve the option A we will get a = -2b.
substituting this value in the main equation will yield a value of 19/3.
Hence the we are able to get a definite value from option A which will be the answer.
SVP  P
Joined: 03 Jun 2019
Posts: 1539
Location: India
Re: What is the value of (8a + a - b)/(a - b) ? (1) (5a + 4b)/(a - b) = 2  [#permalink]

### Show Tags

Bunuel wrote:
What is the value of $$\frac{(8a + a - b)}{(a - b)}$$ ?

(1) $$\frac{(5a + 4b)}{(a - b)} = 2$$

(2) $$a - b = 9$$

Source: GmatFree

Asked: What is the value of $$\frac{(8a + a - b)}{(a - b)}$$ ?

(1) $$\frac{(5a + 4b)}{(a - b)} = 2$$
5a + 4b = 2a - 2b
3a + 6b = 0
a = -2b
$$\frac{(8a + a - b)}{(a - b)} = (-16b -2b -b) / (-2b-b) = (-19b)/(-3b) = 19/3$$
SUFFICIENT

(2) $$a - b = 9$$
We need ratio of a/b to solve
NOT SUFFICIENT

IMO A
_________________
"Success is not final; failure is not fatal: It is the courage to continue that counts."

Please provide kudos if you like my post. Kudos encourage active discussions.

My GMAT Resources: -

Efficient Learning
All you need to know about GMAT quant

Tele: +91-11-40396815
Mobile : +91-9910661622
E-mail : kinshook.chaturvedi@gmail.com
Math Expert V
Joined: 02 Sep 2009
Posts: 58142
Re: What is the value of (8a + a - b)/(a - b) ? (1) (5a + 4b)/(a - b) = 2  [#permalink]

### Show Tags

Bunuel wrote:
What is the value of $$\frac{(8a + a - b)}{(a - b)}$$ ?

(1) $$\frac{(5a + 4b)}{(a - b)} = 2$$

(2) $$a - b = 9$$

Source: GmatFree

Video Explanation

_________________ Re: What is the value of (8a + a - b)/(a - b) ? (1) (5a + 4b)/(a - b) = 2   [#permalink] 19 Sep 2019, 03:15
Display posts from previous: Sort by

# What is the value of (8a + a - b)/(a - b) ? (1) (5a + 4b)/(a - b) = 2

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne  