A store sells a certain product at a fixed price per unit. A : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 24 Jan 2017, 15:49

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# A store sells a certain product at a fixed price per unit. A

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 22 Dec 2011
Posts: 298
Followers: 3

Kudos [?]: 237 [3] , given: 32

A store sells a certain product at a fixed price per unit. A [#permalink]

### Show Tags

04 Oct 2012, 10:35
3
KUDOS
11
This post was
BOOKMARKED
00:00

Difficulty:

55% (hard)

Question Stats:

63% (03:34) correct 37% (02:14) wrong based on 294 sessions

A store sells a certain product at a fixed price per unit. At the product's current price, q units cost a total of exactly $300. If the price were lowered by$5 from its current value, then q + 2n units would cost exactly $300; if the price were raised by$5, then q – n units would cost exactly $300. What is the value of q? A. 10 B. 15 C. 20 D. 25 E. 30 Is there any easy way to solve this problem? Ans is the real exam going to have these sort of problems? Cheers [Reveal] Spoiler: OA Last edited by Bunuel on 04 Oct 2012, 11:27, edited 1 time in total. RENAMED THE TOPIC. Magoosh GMAT Instructor Joined: 28 Dec 2011 Posts: 3720 Followers: 1299 Kudos [?]: 5867 [9] , given: 66 Re: A store sells a certain product at a fixed price per unit. A [#permalink] ### Show Tags 04 Oct 2012, 13:52 9 This post received KUDOS Expert's post 4 This post was BOOKMARKED Jp27 wrote: A store sells a certain product at a fixed price per unit. At the product's current price, q units cost a total of exactly$300. If the price were lowered by $5 from its current value, then q + 2n units would cost exactly$300; if the price were raised by $5, then q – n units would cost exactly$300. What is the value of q?
A. 10
B. 15
C. 20
D. 25
E. 30

Is there any easy way to solve this problem? And is the real exam going to have these sort of problems?

Dear Jp27,

I'm happy to help with this. This problem is very hard --- definitely an upper 700 level question. If you are doing very well on the Quant section, the CAT could feed you a question like this.

This question is a very challenging if you take an algebraic approach, but it's remarkably simple if you backsolve.

Assume q = 20 units
If we can buy 20 units, they must cost a price of 300/20 = $15 Lower the price$5 to a new price of $10 --- then we could buy 300/10 = 30 units (10 more than the original case) Raise the price$5 to a new price of $20 ---- then we could buy 300/20 = 15 units (5 fewer than the original case) This is the case for which we are looking ----- the increase in units from a$5 decrease in price is twice as much as the decrease in units from a $5 increase in price. Does this make sense? Mike _________________ Mike McGarry Magoosh Test Prep Senior Manager Joined: 28 Jun 2009 Posts: 454 Location: United States (MA) Followers: 18 Kudos [?]: 166 [1] , given: 46 Re: A store sells a certain product at a fixed price per unit. A [#permalink] ### Show Tags 04 Oct 2012, 14:09 1 This post received KUDOS It got too complicated when I used algebra. Using plugging in, it was quite fast. Price Quantity total value p q pq = 300 p-5 q+2n (p-5)(q+2n) = 300 p+5 q-n (p+5)(q-n) = 300 Solving three equations for three unknowns. Tough!! Plugging in, I always start with C. C was the answer here, so saved calculation! Putting values in above equations: Price Quantity total value 15 20 300 10 20+2n 300 -> 10(20 + 2n)=300 -> 200 +20n = 300 -> 20n = 100 -> n =5 20 15 300 So q = 20 satisfies all equations!! What is the source? Manager Joined: 26 Jul 2011 Posts: 126 Location: India WE: Marketing (Manufacturing) Followers: 1 Kudos [?]: 109 [0], given: 15 Re: A store sells a certain product at a fixed price per unit. A [#permalink] ### Show Tags 04 Oct 2012, 23:02 As it is said for GMAT "whenever you see yourself dealing with some extra long equations or calculations trust!! there is an easy way out" here in this case back solving makes this question way too easy. B is the answer Senior Manager Joined: 22 Dec 2011 Posts: 298 Followers: 3 Kudos [?]: 237 [0], given: 32 Re: A store sells a certain product at a fixed price per unit. A [#permalink] ### Show Tags 06 Oct 2012, 20:52 mikemcgarry wrote: Jp27 wrote: A store sells a certain product at a fixed price per unit. At the product's current price, q units cost a total of exactly$300. If the price were lowered by $5 from its current value, then q + 2n units would cost exactly$300; if the price were raised by $5, then q – n units would cost exactly$300. What is the value of q?
A. 10
B. 15
C. 20
D. 25
E. 30

Is there any easy way to solve this problem? And is the real exam going to have these sort of problems?

Dear Jp27,

I'm happy to help with this. This problem is very hard --- definitely an upper 700 level question. If you are doing very well on the Quant section, the CAT could feed you a question like this.

This question is a very challenging if you take an algebraic approach, but it's remarkably simple if you backsolve.

Assume q = 20 units
If we can buy 20 units, they must cost a price of 300/20 = $15 Lower the price$5 to a new price of $10 --- then we could buy 300/10 = 30 units (10 more than the original case) Raise the price$5 to a new price of $20 ---- then we could buy 300/20 = 15 units (5 fewer than the original case) This is the case for which we are looking ----- the increase in units from a$5 decrease in price is twice as much as the decrease in units from a $5 increase in price. Does this make sense? Mike Thanks Mike. It does, especially the way you have circumvented calculating the variable N. I guess all the thinking goes before even touching the pen! cheers Intern Status: Fighting to kill GMAT Joined: 23 Sep 2012 Posts: 33 Location: United States Concentration: International Business, General Management Schools: Duke '16 GPA: 3.8 WE: General Management (Other) Followers: 0 Kudos [?]: 18 [0], given: 233 Re: A store sells a certain product at a fixed price per unit. A [#permalink] ### Show Tags 07 Oct 2012, 07:57 piyatiwari wrote: It got too complicated when I used algebra. Using plugging in, it was quite fast. Price Quantity total value p q pq = 300 p-5 q+2n (p-5)(q+2n) = 300 p+5 q-n (p+5)(q-n) = 300 Solving three equations for three unknowns. Tough!! Plugging in, I always start with C. C was the answer here, so saved calculation! Putting values in above equations: Price Quantity total value 15 20 300 10 20+2n 300 -> 10(20 + 2n)=300 -> 200 +20n = 300 -> 20n = 100 -> n =5 20 15 300 So q = 20 satisfies all equations!! What is the source? Is there any reason why you start with C while using POE? What if the numbers are not given in a particular order (ascending here)? Do you use the same strategy in other question types? _________________ Kudos is the currency of appreciation. You can have anything you want if you want it badly enough. You can be anything you want to be and do anything you set out to accomplish, if you hold to that desire with the singleness of purpose. ~William Adams Many of life's failures are people who did not realize how close to success they were when they gave up. ~Thomas A. Edison Wir müssen wissen, Wir werden wissen. (We must know, we will know.) ~Hilbert Senior Manager Joined: 28 Jun 2009 Posts: 454 Location: United States (MA) Followers: 18 Kudos [?]: 166 [0], given: 46 Re: A store sells a certain product at a fixed price per unit. A [#permalink] ### Show Tags 07 Oct 2012, 08:53 closed271 wrote: Is there any reason why you start with C while using POE? What if the numbers are not given in a particular order (ascending here)? Do you use the same strategy in other question types? No reason. I always start with option C while using plugging in. MGMAT advanced math book has some nice techniques about ruling out option choices. But here, I didn't use any of those. Director Joined: 22 Mar 2011 Posts: 612 WE: Science (Education) Followers: 100 Kudos [?]: 894 [1] , given: 43 Re: A store sells a certain product at a fixed price per unit. A [#permalink] ### Show Tags 08 Oct 2012, 08:46 1 This post received KUDOS navigator123 wrote: Jp27 wrote: A store sells a certain product at a fixed price per unit. At the product's current price, q units cost a total of exactly$300. If the price were lowered by $5 from its current value, then q + 2n units would cost exactly$300; if the price were raised by $5, then q – n units would cost exactly$300. What is the value of q?

A. 10
B. 15
C. 20
D. 25
E. 30

Is there any easy way to solve this problem? Ans is the real exam going to have these sort of problems?

Cheers

Since from the options is of pure chance, one would end up losing lots of time.

Any other solution for this question?

Back to the basics.
Write down the prices and corresponding quantities using the given answers. You will get a small table:

(Q, P)
(10, 30)
(15, 20)
(20, 15)
(25, 12)
(30, 10)

From the given information, about raising/reducing the price, you can conclude the following about the prices and corresponding quantities:

Q+2N P-5
Q P
Q-N P+5

The corresponding prices for the quantities Q+2N, Q, and Q-N are three consecutive multiples of 5: P-5, P, and P+5. From the table, the prices should be 10, 15, and 20, and thus the quantity should be 20.

Remark: this is my corrected post, as in my previous one, I mixed up prices and quantities. If somebody saw it, please, just forget about it.
_________________

PhD in Applied Mathematics
Love GMAT Quant questions and running.

Magoosh GMAT Instructor
Joined: 28 Dec 2011
Posts: 3720
Followers: 1299

Kudos [?]: 5867 [3] , given: 66

Re: A store sells a certain product at a fixed price per unit. A [#permalink]

### Show Tags

08 Oct 2012, 12:00
3
KUDOS
Expert's post
closed271 wrote:
Is there any reason why you start with C while using POE? What if the numbers are not given in a particular order (ascending here)? Do you use the same strategy in other question types?

On official GMAT problems, if the answer choices are all single numbers, those numbers will be in numerical order. This is true on all official material and all high quality material, and therefore it's an excellent test of how authentic a given prep source is --- if you see a number of questions with the answers out of order, that's a red flag --- you should question whether that source is trustworthy. Some GMAT prep sources are excellent, and some are not worth the paper on which they are printed.

The reason we start with the middle answer (i.e. (C) on official material) is so that we know which way to go if our first choice is not right. Consider this hypothetical question:
Frank started with X money. He bought blah blah, blah blah, blah % of blah, etc etc and was left with $41.50 in cash after those purchases. What was Frank's original starting amount? (A)$100
(B) $120 (C)$150
(D) $180 (E)$200

I will start with (C) 150 ----- if by chance I'm right, that's great. If I wind up with more leftover cash than $41.50, I know I started with too much --- I can eliminate (C) & (D) & (E). If I wind up with less leftover cash than$41.50, I know I started with too little --- I can eliminate (A) & (B) & (C). Does that make sense?

Mike
_________________

Mike McGarry
Magoosh Test Prep

Current Student
Joined: 26 Jul 2012
Posts: 63
Followers: 0

Kudos [?]: 10 [0], given: 8

Re: A store sells a certain product at a fixed price per unit. A [#permalink]

### Show Tags

10 Nov 2012, 14:00
Even with plugging in this is a humdinger problem!

I tried the algebraic approach first and got stuck. Finally, took a guess.

With plugging in, I will try to time myself but it will take exactly two minutes still.

Case 1:
(x) = Price of the unit
(q) = # of units
Let q = 20
Therefore, x = 15 because qx = 300
Case 2:
x-5 = 10
Given: q + 2n = 30; therefore:
20 + 2n = 30
2n = 10
n = 5

Case 3:
x+5 = 20
Given : q - n = 15
20 - 5 = 15
Done. D is the answer because the equation checks out!
Intern
Joined: 04 Dec 2012
Posts: 15
GMAT 1: 680 Q44 V38
Followers: 0

Kudos [?]: 15 [11] , given: 20

Re: A store sells a certain product at a fixed price per unit. A [#permalink]

### Show Tags

03 Mar 2013, 05:39
11
KUDOS
3
This post was
BOOKMARKED
Hello !

I was reviewing some questions and I think this one is not as difficult as it seems. I solved it in less than 2 minutes using equations solving so I felt like it could be useful to other people :

We can write the following equations :

(1) pq = 300
(2) (q+2n)(p-5) = 300
(3) (q-n)(p+5) = 300

Distribute (2) and (3) :

(2) qp -5q +2np -10n = 300
(3) qp +5q -np - 5n = 300

(2) + (3) : 2qp +np -15n = 600
Thanks to (1) you get : np-15n = 0 or n(p-15) = 0

Since n can't be 0 ( it would mean that a lower or higher price doesn't affect the total price and quantities ) you have p-15 = 0 and p =15. With (1), you get q = 300/15 = 20

I know it seems time consuming but it worked for me. And I usually don't like picking numbers..
Manager
Status: struggling with GMAT
Joined: 06 Dec 2012
Posts: 225
Concentration: Accounting
GMAT Date: 04-06-2013
GPA: 3.65
Followers: 14

Kudos [?]: 346 [0], given: 46

Re: A store sells a certain product at a fixed price per unit. A [#permalink]

### Show Tags

28 Mar 2013, 03:56
pancakeFR wrote:
Hello !

I was reviewing some questions and I think this one is not as difficult as it seems. I solved it in less than 2 minutes using equations solving so I felt like it could be useful to other people :

We can write the following equations :

(1) pq = 300
(2) (q+2n)(p-5) = 300
(3) (q-n)(p+5) = 300

Distribute (2) and (3) :

(2) qp -5q +2np -10n = 300
(3) qp +5q -np - 5n = 300

(2) + (3) : 2qp +np -15n = 600
Thanks to (1) you get : np-15n = 0 or n(p-15) = 0

Since n can't be 0 ( it would mean that a lower or higher price doesn't affect the total price and quantities ) you have p-15 = 0 and p =15. With (1), you get q = 300/15 = 20

I know it seems time consuming but it worked for me. And I usually don't like picking numbers..

Hi
this also works for me.Most of the times i can`t pick the number.1 kudos for u
Intern
Joined: 22 Jan 2010
Posts: 25
Location: India
Concentration: Finance, Technology
GPA: 3.5
WE: Programming (Telecommunications)
Followers: 0

Kudos [?]: 25 [6] , given: 3

Re: A store sells a certain product at a fixed price per unit. A [#permalink]

### Show Tags

28 Mar 2013, 04:08
6
KUDOS
3
This post was
BOOKMARKED
Let p be price per unit.

From the first condition we get pq = 300.

From the other conditions we get,
(p-5)(q+2n) = pq
=> pq -5q + 2pn - 10n = pq
=> 5q = 2pn - 10n

(p+5)(q-n) = pq
=> pq + 5q - pn -5n = pq
=> 5q = pn + 5n -------(3)

so, 2pn - 10n = pn + 5n
=> pn = 15n
=> p = 15
Then q = 300/15 = 20.

-------------------------------------
Please press KUDOS if you like my post.
Manager
Joined: 26 Sep 2013
Posts: 221
Concentration: Finance, Economics
GMAT 1: 670 Q39 V41
GMAT 2: 730 Q49 V41
Followers: 4

Kudos [?]: 141 [0], given: 40

Re: A store sells a certain product at a fixed price per unit. A [#permalink]

### Show Tags

22 Oct 2013, 10:48
mikemcgarry wrote:
Jp27 wrote:
A store sells a certain product at a fixed price per unit. At the product's current price, q units cost a total of exactly $300. If the price were lowered by$5 from its current value, then q + 2n units would cost exactly $300; if the price were raised by$5, then q – n units would cost exactly $300. What is the value of q? A. 10 B. 15 C. 20 D. 25 E. 30 Is there any easy way to solve this problem? And is the real exam going to have these sort of problems? Dear Jp27, I'm happy to help with this. This problem is very hard --- definitely an upper 700 level question. If you are doing very well on the Quant section, the CAT could feed you a question like this. This question is a very challenging if you take an algebraic approach, but it's remarkably simple if you backsolve. Let's start with (C). Assume q = 20 units If we can buy 20 units, they must cost a price of 300/20 =$15
Lower the price $5 to a new price of$10 --- then we could buy 300/10 = 30 units (10 more than the original case)
Raise the price $5 to a new price of$20 ---- then we could buy 300/20 = 15 units (5 fewer than the original case)

This is the case for which we are looking ----- the increase in units from a $5 decrease in price is twice as much as the decrease in units from a$5 increase in price.

Does this make sense?

Mike

I don't get this at all;

based on the first part: 300/(20+2n)=10 (since q=20, the original price was 15 per unit, minus 5 gives you 10), then the 2nd piece gives you 300/(20-n)=20...and I get stuck. What do I do with those two facts. Also, the part highlighted in red, how do you you know you're looking for that case?
Magoosh GMAT Instructor
Joined: 28 Dec 2011
Posts: 3720
Followers: 1299

Kudos [?]: 5867 [2] , given: 66

Re: A store sells a certain product at a fixed price per unit. A [#permalink]

### Show Tags

22 Oct 2013, 11:02
2
KUDOS
Expert's post
AccipiterQ wrote:
A store sells a certain product at a fixed price per unit. At the product's current price, q units cost a total of exactly $300. If the price were lowered by$5 from its current value, then q + 2n units would cost exactly $300; if the price were raised by$5, then q – n units would cost exactly $300. What is the value of q? A. 10 B. 15 C. 20 D. 25 E. 30 This is the case for which we are looking ----- the increase in units from a$5 decrease in price is twice as much as the decrease in units from a $5 increase in price. I don't get this at all; based on the first part: 300/(20+2n)=10 (since q=20, the original price was 15 per unit, minus 5 gives you 10), then the 2nd piece gives you 300/(20-n)=20...and I get stuck. What do I do with those two facts. Also, the part highlighted in red, how do you you know you're looking for that case? Dear AccipiterQ, You seem to be doing the problem with a mix of algebra and backsolving together, which is very very confusing. Do one or the other. For this problem, I believe backsolving is much easier. As always, start with (C) --- suppose q = 20. That means original price is$300/20 = $15. Now, don't do algebra here --- just follow the numerical consequences. If the price is lowered$5 to $10, then we could buy$300/$10 = 30 items, which is q + 10 If the price is raised$5 to $20, then we could buy$300/$20 = 15 items, which is q - 5 The difference between (q + 2p) and (q - p) is that the distance between q and the higher item number (at the lower price) is TWICE the distance between q and the lower item number (at the higher price). Well, here, 10 is twice 5, so we know we have met that condition. Does all this make sense? Mike _________________ Mike McGarry Magoosh Test Prep Manager Joined: 26 Sep 2013 Posts: 221 Concentration: Finance, Economics GMAT 1: 670 Q39 V41 GMAT 2: 730 Q49 V41 Followers: 4 Kudos [?]: 141 [0], given: 40 Re: A store sells a certain product at a fixed price per unit. A [#permalink] ### Show Tags 22 Oct 2013, 12:51 mikemcgarry wrote: AccipiterQ wrote: A store sells a certain product at a fixed price per unit. At the product's current price, q units cost a total of exactly$300. If the price were lowered by $5 from its current value, then q + 2n units would cost exactly$300; if the price were raised by $5, then q – n units would cost exactly$300. What is the value of q?
A. 10
B. 15
C. 20
D. 25
E. 30

This is the case for which we are looking ----- the increase in units from a $5 decrease in price is twice as much as the decrease in units from a$5 increase in price.

I don't get this at all;

based on the first part: 300/(20+2n)=10 (since q=20, the original price was 15 per unit, minus 5 gives you 10), then the 2nd piece gives you 300/(20-n)=20...and I get stuck. What do I do with those two facts. Also, the part highlighted in red, how do you you know you're looking for that case?

Dear AccipiterQ,
You seem to be doing the problem with a mix of algebra and backsolving together, which is very very confusing. Do one or the other.

For this problem, I believe backsolving is much easier.
That means original price is $300/20 =$15.
Now, don't do algebra here --- just follow the numerical consequences.
If the price is lowered $5 to$10, then we could buy $300/$10 = 30 items, which is q + 10
If the price is raised $5 to$20, then we could buy $300/$20 = 15 items, which is q - 5
The difference between (q + 2p) and (q - p) is that the distance between q and the higher item number (at the lower price) is TWICE the distance between q and the lower item number (at the higher price). Well, here, 10 is twice 5, so we know we have met that condition.

Does all this make sense?
Mike

aaaah I get it now, I was creating a stew of algebra & backsolving. Makes perfect sense, thanks!
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13549
Followers: 578

Kudos [?]: 163 [0], given: 0

Re: A store sells a certain product at a fixed price per unit. A [#permalink]

### Show Tags

27 Oct 2014, 13:13
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.
_________________
Intern
Joined: 02 Oct 2014
Posts: 1
Followers: 0

Kudos [?]: 0 [0], given: 0

A store sells a certain product at a fixed price per unit. [#permalink]

### Show Tags

29 Dec 2014, 15:16
A store sells a certain product at a fixed price per unit. At the product's current price, q units cost a total of exactly $300. If the price were lowered by$5 from its current value, then q + 2n units would cost exactly $300; if the price were raised by$5, then q – n units would cost exactly $300. What is the value of q? a: 10 b: 15 c: 20 d: 25 e: 30 in the solution, they say, this problem is to hard to solve with algebra, so they just put in the answer choices and figure out what ist right... That is ok for me, but I don't get how you can se if a problem of this kind is solvable quickly or if it is better just to go with the answer options. Has anybody an advice about that? The problem above didn't look that hard for me so I spent 2 min with it and got the wrong answer:) Director Status: Tutor - BrushMyQuant Joined: 05 Apr 2011 Posts: 583 Location: India Concentration: Finance, Marketing Schools: XLRI (A) GMAT 1: 570 Q49 V19 GMAT 2: 700 Q51 V31 GPA: 3 WE: Information Technology (Computer Software) Followers: 101 Kudos [?]: 572 [1] , given: 55 Re: A store sells a certain product at a fixed price per unit. [#permalink] ### Show Tags 29 Dec 2014, 19:06 1 This post received KUDOS Am not a big fan of substitution so am posting a solution using algebra (doesn't look like a tough equation to solve) We just need to eliminate the variables which we don't really need to compute If we notice the three equations then we can get that "n" is the variable which is making the equations complex for us. So, let eliminate n first Let price be p pq = 300 (p-5)*(q+2n) = 300 => q+2n = 300/(p-5) ...(1) (p+5)*(q-n) = 300 => q-n = 300/(p+5) => 2q - 2n = 600/(p+5) ..(2) Adding (1) and (2), we get 3q = 300/(p-5) + 600/(p-5) Now, we just have two equations in p and q. (Solving for p as the equation looks easy to me) put q = 300/p 900/p = 300/(p-5) + 600/(p+5) 3/p = (p+5 +2p - 10)/(p^2-25) simplifying we get 3p^2 - 75 - 3p^2 + 5p =0 p =15 => q = 20 edsafari wrote: A store sells a certain product at a fixed price per unit. At the product's current price, q units cost a total of exactly$300. If the price were lowered by $5 from its current value, then q + 2n units would cost exactly$300; if the price were raised by $5, then q – n units would cost exactly$300. What is the value of q?

a: 10 b: 15 c: 20 d: 25 e: 30

in the solution, they say, this problem is to hard to solve with algebra, so they just put in the answer choices and figure out what ist right... That is ok for me, but I don't get how you can se if a problem of this kind is solvable quickly or if it is better just to go with the answer options. Has anybody an advice about that? The problem above didn't look that hard for me so I spent 2 min with it and got the wrong answer:)

_________________

Ankit

Check my Tutoring Site -> Brush My Quant

GMAT Quant Tutor
How to start GMAT preparations?
How to Improve Quant Score?
Gmatclub Topic Tags
Check out my GMAT debrief

How to Solve :
Statistics || Reflection of a line || Remainder Problems || Inequalities

Director
Joined: 23 Jan 2013
Posts: 579
Schools: Cambridge'16
Followers: 1

Kudos [?]: 42 [0], given: 40

Re: A store sells a certain product at a fixed price per unit. [#permalink]

### Show Tags

29 Dec 2014, 23:47
have three equations

300/q=p

300/q+2n=p-5

300/q-n=p+5

one option is solving algebraically but it is too long for three variables

started backsolve from q=20 (C)

find that p=15, n=5 and all is OK in this case

C
Re: A store sells a certain product at a fixed price per unit.   [#permalink] 29 Dec 2014, 23:47

Go to page    1   2    Next  [ 23 posts ]

Similar topics Replies Last post
Similar
Topics:
4 A certain manufacturer sells its products to stores in 113 different r 6 03 Jul 2016, 10:05
1 When a certain shoe store reduces the price of its best-selling style 1 19 Jun 2016, 16:34
A certain store sells all maps at one price and all books at another 2 10 Nov 2015, 23:10
1 A company sells Z products, and price per product is y. If the cost of 1 26 Oct 2014, 22:39
4 A store’s selling price of \$2240 for a certain computer would yield a 7 28 Oct 2010, 21:28
Display posts from previous: Sort by