Fox jeans regularly sell for $15 a pair and Pony jeans regularly sell

Kudos

Bookmarks

KarishmaB

Tutor

Joined: 16 Oct 2010

Last visit: 09 Sep 2026

Posts: 16,648

Location: Pune, India

Expert

Expert reply

Posts: 16,648

02 Feb 2011, 20:23

shanewyatt

Can find total price without discount ($81) and price after discount ($72), but not sure where to go from there.

Note: When I look at this question, my first instinct is to check if the split is 10% and 12%. The reason is that it is a lucky twin... i.e. when I split 22% to get one part as 10%, the other is 12%. When one part is 9%, the other is 13% (not there in options). When one part is 15%, the other is 7% (not there in options). 11% cannot be because the discount rates are different. I am not saying this strategy will always work, but this is what I will always start with because it has the maximum probability of being correct.

Why? Because it is the tendency of the question setter to give one option as 12% too even if the correct answer is 10% because it is a pit for someone who is careless. Say, one found that the 22% is split into 10 and 12 but while answering the question, made a mistake of marking the discount on Fox jeans rather than Pony jeans... Bang!

So watch out for lucky twins especially in probability questions!

_________________

-
Start FREE with selected GMAT/EA Content upon registration at anaprep.com

YouTube Channel: karishma.anaprep

Kudos

Bookmarks

General Discussion

craky

Joined: 27 Jul 2010

Last visit: 29 Jan 2013

Posts: 101

Location: Prague

Schools:University of Economics Prague

GMAT 1: 700 Q48 V38 Verified score

Posts: 101

02 Feb 2011, 10:09

Thanks bunuel, even faster solution than with 2 equasions.

Kudos

Bookmarks

subhashghosh

Retired Moderator

Joined: 16 Nov 2010

Last visit: 24 Jun 2024

Posts: 894

Location: United States (IN)

Concentration: Strategy, Technology

Products:

Posts: 894

13 Mar 2011, 05:12

Let x be the discount on Fox Jeans
Let y be the discount on Pony Jeans

x + y = 22

x/100* 15 * 3 + y/100 * 18 * = 9

Solving these we get y = 10, so the answer is B.

Kudos

Bookmarks

Yalephd

Joined: 03 Aug 2010

Last visit: 31 Oct 2019

Posts: 67

GMAT Date: 08-08-2011

Posts: 67

16 Apr 2011, 12:30

I follow the 10 / 12 split, but how would you end up choosing 10 over 12 using the lucky twin strategy for this question?

VeritasPrepKarishma

shanewyatt

Can find total price without discount ($81) and price after discount ($72), but not sure where to go from there.

Kudos

Bookmarks

IanStewart

GMAT Tutor

Joined: 24 Jun 2008

Last visit: 09 Sep 2026

Posts: 4,146

Location: United States

GMAT 1: 780 Q51 V47 Verified score

Expert

Expert reply

GMAT 1: 780 Q51 V47 Verified score

Posts: 4,146

16 Apr 2011, 13:24

VeritasPrepKarishma

That might sound plausible, and I've certainly read about the 'trick' of identifying 'twin' answer choices many times, but in practice it is completely pointless to look for twinned answer choices. I looked at all the official questions in the OG and the Official Quant Review to see how often you'd answer correctly if you always guessed that a 'twin' answer was correct. It turns out you'd do (very slightly) worse by guessing a 'twin' than if you just guessed at random. I posted details here:

spaceland-prep-strategy-question-110923.html

_________________

now teaching gmat focus

ianstewartgmat.com

Kudos

Bookmarks

Spidy001

Joined: 01 Feb 2011

Last visit: 16 Feb 2015

Posts: 298

16 Apr 2011, 16:44

Let x and y are discount rates on Fox and Pony jeans respectively.

=> 3(15)(x) + 2*18(0.22-x) = 9

=> x = 12% and y =10%

Answer is B.

Kudos

Bookmarks

KarishmaB

Tutor

Joined: 16 Oct 2010

Last visit: 09 Sep 2026

Posts: 16,648

Location: Pune, India

Expert

Expert reply

Posts: 16,648

16 Apr 2011, 18:11

Yalephd

I follow the 10 / 12 split, but how would you end up choosing 10 over 12 using the lucky twin strategy for this question?

It is a guess. The way it helps me is that I will first check for the 10/12 split. If it doesn't work out, I will check the other options. You have to solve to get to the right answer.
Say if the % offered on Pony jeans ($18) is 10%, I am getting a discount of 1.8 on each pair of jeans. If I am getting 12% discount on Fox jeans($15), I am saving $1.8 on each pair of Fox jeans (you can calculate this orally and quickly - 10% of 15 is 1.5; 1% of 15 is 0.15 so 2% is 0.3, hence 12% of 15 is 1.5+0.3 = $1.8. If it seems too cumbersome, it is only because of lack of practice; it actually happens in a flash once you are used to it!)
On 3 pairs of Fox jeans and 2 pairs of Pony jeans, I will save 5*1.8 = $9
Since $9 is the given discount, our assumption is correct and the discount of Pony jeans must be 10%.

_________________

-
Start FREE with selected GMAT/EA Content upon registration at anaprep.com

YouTube Channel: karishma.anaprep

Kudos

Bookmarks

gmat1220

Joined: 03 Feb 2011

Last visit: 17 Feb 2020

Posts: 461

Status:Impossible is not a fact. It's an opinion. It's a dare. Impossible is nothing.

Affiliations: University of Chicago Booth School of Business

Products:

Posts: 461

17 Apr 2011, 11:20

Karishma

Considering the weights - 3 and 2 (3 pairs of fox and 2 pairs of pony) - that he saved (12/10 discount) more by buying more of the fox jeans than pony jeans ? Is this thinking correct? i.e. more discount on the fox.

Or the opposite

He could have saved more by more discount on the pony - since the pony is priced for $3 more ($18 per pair) Hence we must rule out the option D before guessing option B. What do you think?

VeritasPrepKarishma

Kudos

Bookmarks

KarishmaB

Tutor

Joined: 16 Oct 2010

Last visit: 09 Sep 2026

Posts: 16,648

Location: Pune, India

Expert

Expert reply

Posts: 16,648

17 Apr 2011, 16:58

gmat1220

I think the way you are thinking is pretty great but I did not understand what is 12/10 discount.

If you want to consider weights, say, if you know that the answer is either 10-12 or 12-10, you can think this way:
3 Fox jeans price = $45
2 Pony jeans price = $36
So you got a discount of $9 on $81 which is 1/9 i.e. 11.11% discount. Since Fox jeans total cost price is higher than Pony jeans total cost price, the discount of Fox jeans must be 12% and that of Pony jeans must be 10% to give an average discount of 11.11% i.e. a value closer to 12% than to 10%.

_________________

-
Start FREE with selected GMAT/EA Content upon registration at anaprep.com

YouTube Channel: karishma.anaprep

Kudos

Bookmarks

ScottTargetTestPrep

Target Test Prep Representative

Joined: 14 Oct 2015

Last visit: 09 Sep 2026

Posts: 22,736

Status:Founder & CEO

Affiliations: Target Test Prep

Location: United States (CA)

Expert

Expert reply

Posts: 22,736

12 Sep 2019, 10:35

shanewyatt

At the regular prices, 3 pairs of Fox jeans and 2 pairs of Pony jeans would cost 3 x 15 + 2 x 18 = 45 + 36 = $81. Since a total of $9 is saved at the discounted prices, the cost of the same 5 pairs of jeans is now $72. Since the sum of the 2 discount rates is 22%, we can let n/100 = the discount rate of Pony jeans and (22 - n)/100 = the discount rate of Fox jeans and create the equation:

3 x 15 x (1 - (22 - n)/100) + 2 x 18 x (1 - n/100) = 72

Multiplying the equation by 100, we have:

45 x (100 - (22 - n)) + 36 x (100 - n) = 7200

45 x (78 + n) + 3600 - 36n = 7200

3510 + 45n - 36n = 3600

9n = 90

n = 10

Thus, the discount rate of Pony jeans is n/100 = 10/100 = 10%.

Answer: B

_________________

Scott Woodbury-Stewart | Founder and CEO | [email protected]

OnDemand, the Most Comprehensive Video Course
Try 5 Days of Self-Study for FREE
Get 2 Extra Weeks for FREE
130-Score Improvement Guarantee

See why Target Test Prep is the top rated GMAT course on GMAT Club. Read Our Reviews

Kudos

Bookmarks

rickyric395

Joined: 07 Mar 2020

Last visit: 14 Aug 2026

Posts: 122

GMAT 1: 680 Q49 V34 Verified score

Posts: 122

08 Mar 2023, 22:23

Spidy001

Let x and y are discount rates on Fox and Pony jeans respectively.

=> 3(15)(x) + 2*18(0.22-x) = 9

=> x = 12% and y =10%

Answer is B.

Hey Spidy001 9$ is saved money so isn't the 2nd equation be original price - discounted price = saved money ?

Kudos

Bookmarks

rickyric395

Joined: 07 Mar 2020

Last visit: 14 Aug 2026

Posts: 122

GMAT 1: 680 Q49 V34 Verified score

Posts: 122

08 Mar 2023, 22:27

Bunuel

Hey Bunuel , saved money is 9$ , then isn't that should be original price - discounted price = saved money . What am I missing ?

Kudos

Bookmarks

Bunuel

Math Expert

Joined: 02 Sep 2009

Last visit: 10 Sep 2026

Posts: 113,351

Products:

Expert

Expert reply

Posts: 113,351

08 Mar 2023, 23:28

rickyric395

Bunuel

Hey Bunuel , saved money is 9$ , then isn't that should be original price - discounted price = saved money . What am I missing ?

Yes, you could do that way too:

(3*15 + 2*18) - (3*15*(1 - (0.22 - x)) + 2*18*(1 - x)) = 9
If you simplify the above you get the same equation I have:

3*15(0.22 - x) + 2*18x = 9
My equation, represents the following:

Amount of the discount on Fox jeans + Amount of the discount on Pony jeans = $9.
Does this help?

_________________

New to the GMAT Club?

Kudos

Bookmarks

rickyric395

Joined: 07 Mar 2020

Last visit: 14 Aug 2026

Posts: 122

GMAT 1: 680 Q49 V34 Verified score

Posts: 122

09 Mar 2023, 04:21

Bunuel

rickyric395

Bunuel

Hey Bunuel , saved money is 9$ , then isn't that should be original price - discounted price = saved money . What am I missing ?

Yes, you could do that way too:

(3*15 + 2*18) - (3*15*(1 - (0.22 - x)) + 2*18*(1 - x)) = 9
If you simplify the above you get the same equation I have:

3*15(0.22 - x) + 2*18x = 9
My equation, represents the following:

Amount of the discount on Fox jeans + Amount of the discount on Pony jeans = $9.
Does this help?

Hey Bunuel, from the stem , I formed 2 equations 1) $x+y=22$ 2) $3*15*(1-\frac{x}{100}) + 2*18*(1-\frac{y}{100})$
But I guess i have made some mistake. Can you please point it to me?

Kudos

Bookmarks

Bunuel

Math Expert

Joined: 02 Sep 2009

Last visit: 10 Sep 2026

Posts: 113,351

Products:

Expert

Expert reply

Posts: 113,351

09 Mar 2023, 04:39

rickyric395

Hey Bunuel, from the stem , I formed 2 equations 1) $x+y=22$ 2) $3*15*(1-\frac{x}{100}) + 2*18*(1-\frac{y}{100})$
But I guess i have made some mistake. Can you please point it to me?

There is no second equation in your post. What does this expression represent: $3*15*(1-\frac{x}{100}) + 2*18*(1-\frac{y}{100})$ ?

_________________

New to the GMAT Club?

Kudos

Bookmarks

rickyric395

Joined: 07 Mar 2020

Last visit: 14 Aug 2026

Posts: 122

GMAT 1: 680 Q49 V34 Verified score

Posts: 122

09 Mar 2023, 05:06

Bunuel

rickyric395

Hey Bunuel, from the stem , I formed 2 equations 1) $x+y=22$ 2) $3*15*(1-\frac{x}{100}) + 2*18*(1-\frac{y}{100})$
But I guess i have made some mistake. Can you please point it to me?

There is no second equation in your post. What does this expression represent: $3*15*(1-\frac{x}{100}) + 2*18*(1-\frac{y}{100})$ ?

Sorry , I missed writing the complete 2nd equation.
1st eqn is $x+y=22$ ----- (from sum of rate of discount as 22)
2nd eqn is $3*15*(1-\frac{x}{100}) + 2*18*(1-\frac{y}{100})=9$ ----- (money saved is 9$)

Kudos

Bookmarks

Bunuel

Math Expert

Joined: 02 Sep 2009

Last visit: 10 Sep 2026

Posts: 113,351

Products:

Expert

Expert reply

Posts: 113,351

09 Mar 2023, 05:11

rickyric395

Bunuel

rickyric395

Hey Bunuel, from the stem , I formed 2 equations 1) $x+y=22$ 2) $3*15*(1-\frac{x}{100}) + 2*18*(1-\frac{y}{100})$
But I guess i have made some mistake. Can you please point it to me?

There is no second equation in your post. What does this expression represent: $3*15*(1-\frac{x}{100}) + 2*18*(1-\frac{y}{100})$ ?

If the discount on Pony jeans is say 10%, then 2*18*0.10 gives the amount of the discount, while 2*18*(1 - 0.1) gives the amount paid. You are mixing these two.

_________________

New to the GMAT Club?