GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

 It is currently 02 Jun 2020, 07:58 ### 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.  # If each of a, b and c is positive, and a = 5b + 7c, what is

Author Message
TAGS:

### Hide Tags

Intern  Joined: 12 Aug 2010
Posts: 13
If each of a, b and c is positive, and a = 5b + 7c, what is  [#permalink]

### Show Tags

1
2 00:00

Difficulty:   55% (hard)

Question Stats: 64% (01:58) correct 36% (02:00) wrong based on 147 sessions

### HideShow timer Statistics

If each of a, b and c is positive, and a = 5b + 7c, what is the value of a/b?

1) 2b + 5c = 50
2) 3b - 5c = c
Math Expert V
Joined: 02 Sep 2009
Posts: 64172
Re: Is it a hard question  [#permalink]

### Show Tags

chiragatara wrote:
If each of a, b and c is positive, and a = 5b + 7c, what is the value of a/b?

1) 2b + 5c = 50
2) 3b - 5c = c

Given: $$a=5b+7c$$.

Now, as we are asked to get the value of $$\frac{a}{b}$$ then divide both parts of $$a=5b+7c$$ by $$b$$ (to have LHS equal to $$\frac{a}{b}$$): $$\frac{a}{b}=5+7\frac{c}{b}$$. So, basically finding the value of $$\frac{c}{b}$$ will be sufficient.

(1) 2b + 5c = 50 --> we can neither solve for unknowns (2 distinct linear equations, 3 variables) nor get the desired ratio. Not sufficient.
(2) 3b - 5c = c --> $$3b=6c$$ --> $$\frac{c}{b}=\frac{1}{2}$$. Sufficient.

_________________
Current Student B
Status: DONE!
Joined: 05 Sep 2016
Posts: 336
Re: If each of a, b and c is positive, and a = 5b + 7c, what is  [#permalink]

### Show Tags

B is correct. Here's why:

(1) 2b +5c = 50

NOT SUFFICIENT - we don't have any way to get a/b

(2) c = 3b - 5c --> Simplifies to 6c = 3b --> b = 2c

We know from the beginning of the question that a = 5b+7c --> Plug b = 2c and you arrive at a = 17c

Thus a/b = 17/2
Non-Human User Joined: 09 Sep 2013
Posts: 15041
Re: If each of a, b and c is positive, and a = 5b + 7c, what is  [#permalink]

### Show Tags

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________ Re: If each of a, b and c is positive, and a = 5b + 7c, what is   [#permalink] 05 Jan 2019, 04:54

# If each of a, b and c is positive, and a = 5b + 7c, what is  