BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

At the beginning of February, the ratio of goats to pigs on

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 421
Joined: Sun Apr 17, 2011 4:27 am
Location: India
Thanked: 6 times
Followed by:2 members
GMAT Score:620

At the beginning of February, the ratio of goats to pigs on

by vinni.k » Mon Jun 04, 2018 10:24 am
At the beginning of February, the ratio of goats to pigs on a certain farm was 7 to 6. What was the ratio of goats to pigs at the end of February?

(1) During the month of February, the number of goats doubled.

(2) During the month of February, the number of pigs decreased by 50%

OA is C

I don't know why i am inclined towards D..if nothing is said about pigs in (1) then i think they remain unchanged..similarly (2)

or if i am wrong then C

Initial
Goat: Pig
7:6

using both (1) & (2)
Final
Goat: Pig
14:3

Between C & D ,, i will go with D
Top
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
Elite Legendary Member
Posts: 10392
Joined: Sun Jun 23, 2013 6:38 pm
Location: Palo Alto, CA
Thanked: 2867 times
Followed by:511 members
GMAT Score:800

by [email protected] » Wed Jun 06, 2018 8:47 pm
Hi vinni.k,

We're told that at the beginning of February, the ratio of goats to pigs on a certain farm was 7 to 6 - meaning that the number of goats MUST be a multiple of 7 and the number of pigs MUST be a multiple of 6 (for example, 7 goats and 6 pigs, 14 goats and 12 pigs, 21 goats and 18 pigs, etc.). We're asked for the RATIO of goats to pigs at the END of February. This question can be solved in a number of different ways, including "ratio math."

1) During the month of February, the number of goats doubled.

Fact 1 tells us NOTHING about what happens to the number of pigs, so there's no way to determine the end ratio.
Fact 1 is INSUFFICIENT

2) During the month of February, the number of pigs decreased by 50%

Fact 2 tells us NOTHING about what happens to the number of goats, so there's no way to determine the end ratio.
Fact 2 is INSUFFICIENT

Combined, we know:
During the month of February, the number of goats doubled.
During the month of February, the number of pigs decreased by 50%

You correctly adjusted the beginning ratio to account for this information (re: doubling the goats and halving the pigs), which gives us a final ratio of (2)(7):(1/2)(6) = 14:3
Combined, SUFFICIENT

Final Answer: C

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 421
Joined: Sun Apr 17, 2011 4:27 am
Location: India
Thanked: 6 times
Followed by:2 members
GMAT Score:620

by vinni.k » Thu Jun 07, 2018 10:20 am
I think i am pretty convinced. I understood my mistake.

Thanks. Really appreciate it.
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 2095
Joined: Tue Dec 04, 2012 3:22 pm
Thanked: 1443 times
Followed by:247 members

by ceilidh.erickson » Fri Jun 08, 2018 11:26 am
vinni.k wrote:At the beginning of February, the ratio of goats to pigs on a certain farm was 7 to 6. What was the ratio of goats to pigs at the end of February?

(1) During the month of February, the number of goats doubled.

(2) During the month of February, the number of pigs decreased by 50%

OA is C

I don't know why i am inclined towards D..if nothing is said about pigs in (1) then i think they remain unchanged..similarly (2)
You've answered your own question here! This is a common assumption to make... and the GMAT knows this and will exploit it. We can never assume that any situation will hold steady over time unless we're explicitly told so.

Even if you held this assumption that "no info about pigs = pigs stayed the same" when evaluating statement 1, that should have changed when you read statement 2 and saw that the number of pigs had changed. Remember that statements must be true, so they cannot contradict each other. Sometimes evaluating one statement can point out ow we've misinterpreted the other.

Btw, this assumption about situations holding steady over time will often be tested in CR. Consider this:
Company X's revenue went up by 20% since last year, so they must be making a greater profit.
What is the author assuming? That all other circumstances (namely costs) stayed the same over than time. We can't assume this!
Ceilidh Erickson
EdM in Mind, Brain, and Education
Harvard Graduate School of Education
Top
User avatar
Junior | Next Rank: 30 Posts
Posts: 26
Joined: Thu May 22, 2014 3:06 am

Ratio

by jabhatta » Wed Dec 18, 2019 5:59 pm
ceilidh.erickson wrote:
vinni.k wrote:At the beginning of February, the ratio of goats to pigs on a certain farm was 7 to 6. What was the ratio of goats to pigs at the end of February?



(1) During the month of February, the number of goats doubled.

(2) During the month of February, the number of pigs decreased by 50%

OA is C

I don't know why i am inclined towards D..if nothing is said about pigs in (1) then i think they remain unchanged..similarly (2)
You've answered your own question here! This is a common assumption to make... and the GMAT knows this and will exploit it. We can never assume that any situation will hold steady over time unless we're explicitly told so.

Even if you held this assumption that "no info about pigs = pigs stayed the same" when evaluating statement 1, that should have changed when you read statement 2 and saw that the number of pigs had changed. Remember that statements must be true, so they cannot contradict each other. Sometimes evaluating one statement can point out ow we've misinterpreted the other.

Btw, this assumption about situations holding steady over time will often be tested in CR. Consider this:
Company X's revenue went up by 20% since last year, so they must be making a greater profit.
What is the author assuming? That all other circumstances (namely costs) stayed the same over than time. We can't assume this!

Hello @ceilidh.erickson

Per blue above -- you mentioned they cannot contradict each other.

While I agree S1 is not talking about pigs wheres S2 is not talking about goats -- how are the statement contradicting each other when both S1 and S2 are giving us the same ratio ?

S1-- Given number of goats is doubled, the ratio is now 14 : 6 or 7 : 3

S2 -- Given number of pigs is halved -- the ratio is now 7 : 3

So S1 and S2 are not contradicting each other based on the ratio being generated by the two statements independent of each other

How do you reconcile that while S1 is not talking about pigs and S2 -- is not talking about goats -- they both somehow are generating the same ratio (7 :3 )

Please let me know your thoughts !

Somehow the ratio's are coming up to be the same, i.e 7 : 3
Top
Post new topic Post Reply
• Page 1 of 1