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Updated on: 13 Feb 2014, 07:15
1
00:00

Difficulty:

45% (medium)

Question Stats:

77% (02:29) correct 23% (02:35) wrong based on 103 sessions

Mr. John used to purchase certain number of mangoes for $360 Since the price of mangoes is reduced by 10% he got 12 more mangoes today. Find the original price of 120 mangoes. A. 360 B. 380 C. 400 D. 406 E. 412 _________________ If the Q jogged your mind do Kudos me : ) Originally posted by rxs0005 on 28 Jul 2010, 06:55. Last edited by Bunuel on 13 Feb 2014, 07:15, edited 1 time in total. Renamed the topic, edited the question and added the OA. Manager Joined: 11 Feb 2008 Posts: 79 Re: Percent [#permalink] Show Tags 28 Jul 2010, 07:57 C - no of mangoes (360/0.9C)-(360/C)=12 C=10/3 120 mangoes should cost 400 _________________ ------------------------------------------------------------------------------------------- Amar http://amarnaik.wordpress.com Manager Joined: 02 Apr 2010 Posts: 101 Re: Percent [#permalink] Show Tags 28 Jul 2010, 09:22 1 x = price per mango y = number of mangoes Equation 1: x*y = 360 => y = 360/x Equation 2: x*0.9*(y+12) = 360 Replace y in equation with 360/x (obtained from Equation 1 and solve for x) => x = 10/3 Multiplying with 120 (number of mangoes the question asks for) yields (10/3)*120 = 400 SVP Joined: 06 Sep 2013 Posts: 1796 Concentration: Finance Re: Percent [#permalink] Show Tags 13 Feb 2014, 06:53 1 Im trying to answer this another way but I can't seem to think what I'm doing wrong So we have PQ = 360 (0.9P)(Q+12) = 360 We need to find 120P Now if we reduce 10% on P and still get the same result then Q increases 10% So Q + 12 = 11/10 Q --> Q = 120 Therefore P is equal to 3. And we have that 120P = 360. I don't quite know what I can't get the answer 400 following this approach, could any expert please advise Thanks a lot! Cheers J Math Expert Joined: 02 Sep 2009 Posts: 49496 Re: Percent [#permalink] Show Tags 13 Feb 2014, 07:38 1 jlgdr wrote: Mr. John used to purchase certain number of mangoes for$360 Since the price of mangoes is reduced by 10% he got 12 more mangoes today. Find the original price of 120 mangoes.

A. 360
B. 380
C. 400
D. 406
E. 412

Im trying to answer this another way but I can't seem to think what I'm doing wrong

So we have

PQ = 360
(0.9P)(Q+12) = 360

We need to find 120P

Now if we reduce 10% on P and still get the same result then Q increases 10%
So Q + 12 = 11/10 Q --> Q = 120

Therefore P is equal to 3.

And we have that 120P = 360.

I don't quite know what I can't get the answer 400 following this approach, could any expert please advise

Thanks a lot!
Cheers
J

P reduces 9/10 times, thus Q increases 10/9 times: Q + 12 = 10/9*Q --> Q = 108.

Alternatively you could solve the system of equations: PQ = 360 and (0.9P)(Q+12) = 360 to get the same result.
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13 Feb 2014, 09:02
Bunuel wrote:
jlgdr wrote:
Mr. John used to purchase certain number of mangoes for $360 Since the price of mangoes is reduced by 10% he got 12 more mangoes today. Find the original price of 120 mangoes. A. 360 B. 380 C. 400 D. 406 E. 412 Im trying to answer this another way but I can't seem to think what I'm doing wrong So we have PQ = 360 (0.9P)(Q+12) = 360 We need to find 120P Now if we reduce 10% on P and still get the same result then Q increases 10% So Q + 12 = 11/10 Q --> Q = 120 Therefore P is equal to 3. And we have that 120P = 360. I don't quite know what I can't get the answer 400 following this approach, could any expert please advise Thanks a lot! Cheers J P reduces 9/10 times, thus Q increases 10/9 times: Q + 12 = 10/9*Q --> Q = 108. Alternatively you could solve the system of equations: PQ = 360 and (0.9P)(Q+12) = 360 to get the same result. I see were my mistake was. Well but replacing and all into (2) is too much work. Once with Q then you can solve much easier in my opinion Thanks again buddy Cheers J Math Expert Joined: 02 Sep 2009 Posts: 49496 Re: Percent [#permalink] Show Tags 13 Feb 2014, 10:16 jlgdr wrote: Bunuel wrote: jlgdr wrote: Mr. John used to purchase certain number of mangoes for$360 Since the price of mangoes is reduced by 10% he got 12 more mangoes today. Find the original price of 120 mangoes.

A. 360
B. 380
C. 400
D. 406
E. 412

Im trying to answer this another way but I can't seem to think what I'm doing wrong

So we have

PQ = 360
(0.9P)(Q+12) = 360

We need to find 120P

Now if we reduce 10% on P and still get the same result then Q increases 10%
So Q + 12 = 11/10 Q --> Q = 120

Therefore P is equal to 3.

And we have that 120P = 360.

I don't quite know what I can't get the answer 400 following this approach, could any expert please advise

Thanks a lot!
Cheers
J

P reduces 9/10 times, thus Q increases 10/9 times: Q + 12 = 10/9*Q --> Q = 108.

Alternatively you could solve the system of equations: PQ = 360 and (0.9P)(Q+12) = 360 to get the same result.

I see were my mistake was. Well but replacing and all into (2) is too much work. Once with Q then you can solve much easier in my opinion

Thanks again buddy
Cheers
J

Actually you can get $$Q + 12 = \frac{10}{9}*Q$$ from the system of equations we have quite easily. Divide $$(0.9P)(Q+12) = 360$$ by $$PQ = 360$$:

$$\frac{0.9(Q+12)}{Q} = 1$$ --> $$0.9(Q+12) = Q$$ --> $$Q + 12 = \frac{10}{9}*Q$$.

Hope it helps.
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Posts: 34
Re: Mr.John used to purchase certain number of mangoes for $360. [#permalink] Show Tags 13 Feb 2014, 10:55 Mr. John used to purchase certain number of mangoes for$360 Since the price of mangoes is reduced by 10% he got 12 more mangoes today. Find the original price of 120 mangoes.

Method 1:
Let price per mango = x. Let number of mangoes be n. Then, nx = 360.
Now price = 0.9x; number of mangoes = n + 12. Total amount = 0.9x*(n+12) = 360.
nx = 0.9nx + 10.8x => 0.1nx = 10.8x => n = 108 => x = 360/108 = 3.33
Original price of 120 mangoes = 120*3.33 = 400.

Method 2:
Let price per mango be x. Then, 360/(0.9x) - 360/x = 12
=> 400/x - 360/x = 12 => 40/x = 12 => x = 40/12.
Price of 120 mangoes = 120 x = 120 *40/12 = 400
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06 Sep 2018, 03:57
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Re: Mr.John used to purchase certain number of mangoes for $360. &nbs [#permalink] 06 Sep 2018, 03:57 Display posts from previous: Sort by Mr.John used to purchase certain number of mangoes for$360.

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