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# The price of lunch for 15 people was $207.00, including a 15  Question banks Downloads My Bookmarks Reviews Important topics Author Message TAGS: Director Status: Preparing for the 4th time -:( Joined: 25 Jun 2011 Posts: 560 Location: United Kingdom Concentration: International Business, Strategy GMAT Date: 06-22-2012 GPA: 2.9 WE: Information Technology (Consulting) Followers: 14 Kudos [?]: 790 [2] , given: 217 The price of lunch for 15 people was$207.00, including a 15 [#permalink]  02 May 2012, 14:55
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63% (02:32) correct 37% (01:27) wrong based on 579 sessions
The price of lunch for 15 people was $207.00, including a 15 percent gratuity for service. What was the average price per person, EXCLUDING the gratuity? (A)$11.73
(B) $12.00 (C)$13.80
(D) $14.00 (E)$15.87

[Reveal] Spoiler:
How come the answer is B?

This is how I solved it and got A, which is incorrect.

$207 includes 15% gratuity so 0.15 * 207 = 31.05 Price EXCLUDING gratuity = 207 - 31.05 = 175.95 Average price per person = 175.95/15 = 11.73 [Reveal] Spoiler: OA _________________ Best Regards, E. MGMAT 1 --> 530 MGMAT 2--> 640 MGMAT 3 ---> 610 Director Status: Joined: 24 Jul 2011 Posts: 557 GMAT 1: 780 Q51 V48 GRE 1: 1540 Q800 V740 Followers: 72 Kudos [?]: 304 [1] , given: 11 Re: Price of lunch [#permalink] 02 May 2012, 20:23 1 This post received KUDOS The mistake you have made is that you have calculated the gratuity on the final amount, instead of finding the amount on which gratuity was charged to get the final amount. If the amount spent excluding the gratuity was x, then x(1.15) = 207 => x = 207/1.15 = 180 Then the average price per person = 180/15 = 12 Option (B) _________________ GyanOne | http://www.GyanOne.com | +91 9899831738 Manager Joined: 02 Jun 2011 Posts: 160 Followers: 1 Kudos [?]: 29 [0], given: 11 Re: Price of lunch [#permalink] 03 May 2012, 01:48 GyanOne wrote: The mistake you have made is that you have calculated the gratuity on the final amount, instead of finding the amount on which gratuity was charged to get the final amount. If the amount spent excluding the gratuity was x, then x(1.15) = 207 => x = 207/1.15 = 180 Then the average price per person = 180/15 = 12 Option (B) gratuity is charged on final amount then is it not obvious to calculate such as! just wish to have clarification on the two : 1.) 270 - 15% of 270 = 175.95/ 15 = 11.73 2.) if 115 is 270 then 100 = 180 and 180/15 = 12 is it not the same thing ? Intern Joined: 13 Nov 2010 Posts: 42 Followers: 0 Kudos [?]: 15 [2] , given: 2 Re: The price of lunch for 15 people was$207 including a 15% [#permalink]  03 May 2012, 06:51
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enigma123 wrote:
The price of lunch for 15 people was $207 including a 15% gratuity for service. What was the average price per person, EXCLUDING the gratuity? A. 11.73 B. 12 C. 13.8 D. 14 E. 15.87 How come the answer is B? This is how I solved it and got A, which is incorrect.$207 includes 15% gratuity so 0.15 * 207 = 31.05

Price EXCLUDING gratuity = 207 - 31.05 = 175.95

Average price per person = 175.95/15 = 11.73

I'll show You perhaps the most easiest way to solve such problem

As it is a percentage problem so just take the initial price before the gratuity is 100 the as the gratuity is calculated on the final price, so as we assumed the final bill before adding gratuity is 100 so gratuity is 15% of 100 is 15 so the total price of meals is 115 so the given amount i.e 207 is for 115 then we have to calculate for 100 here we go

for 115 207
for 100 x

so by cross multiplication we get 115x=100*207 => x=100*207/110 by simplifying we get x as 180 which is the price of lunch before gratuity so the gratuity is 27 so

as the question ask the average price person excluding gratuity is 180/15=12 so our answer is b

hope its concise and clear .

if u satisfied with my effort don't hesitate to give +1 kudos.
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Re: Price of lunch [#permalink]  03 May 2012, 11:56
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Expert's post
kashishh wrote:
GyanOne wrote:
The mistake you have made is that you have calculated the gratuity on the final amount, instead of finding the amount on which gratuity was charged to get the final amount.

If the amount spent excluding the gratuity was x, then x(1.15) = 207
=> x = 207/1.15 = 180

Then the average price per person = 180/15 = 12

Option (B)

gratuity is charged on final amount then is it not obvious to calculate such as!

just wish to have clarification on the two :
1.) 270 - 15% of 270 = 175.95/ 15 = 11.73

2.) if 115 is 270 then 100 = 180 and 180/15 = 12

is it not the same thing ?

Tip is charged on the bill. Consider this: the bill is $100 and tip is 15% means that total amount paid is 100+15=$115.

The price of lunch for 15 people was $207 including a 15% gratuity for service. What was the average price per person, EXCLUDING the gratuity? A. 11.73 B. 12 C. 13.8 D. 14 E. 15.87 Bill*1.15=$207 --> Bill=$180 --> per person=$180/15=$12. Answer: B. _________________ Manager Joined: 17 Sep 2011 Posts: 209 Followers: 0 Kudos [?]: 28 [0], given: 8 The price of lunch for 15 people was$207 including a 15% [#permalink]  10 May 2012, 02:22
The solution is :

207 * .15 = 31.05 ==> 207 - 31.05 = 175.95==> 175.95 / 15 = 11.73
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Re: The price of lunch for 15 people was $207 including a 15% [#permalink] 14 May 2012, 05:10 enigma123 wrote: The price of lunch for 15 people was$207 including a 15% gratuity for service. What was the average price per person, EXCLUDING the gratuity?

A. 11.73
B. 12
C. 13.8
D. 14
E. 15.87

How come the answer is B?

This is how I solved it and got A, which is incorrect.

$207 includes 15% gratuity so 0.15 * 207 = 31.05 Price EXCLUDING gratuity = 207 - 31.05 = 175.95 Average price per person = 175.95/15 = 11.73 Hello here is my approach so let x be the sum of the 15 lunch WITHOUT the 15 % 1.15 X = 207 X = 207/ 1.15 X= 180 so 180 is for 15 people the average price be 180 /15= 12 HENCE B HOPE THIS HELP BEST REGARDS Intern Joined: 19 Dec 2011 Posts: 21 Followers: 0 Kudos [?]: 7 [1] , given: 37 The price of lunch for 15 people was$207.00, including a [#permalink]  25 Aug 2012, 11:33
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check the option :

12

12 * 15 = 180

180 + [ 18 + 9 ] ( 15 % of 180) = 207
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Re: The price of lunch for 15 people was $207 including a 15% [#permalink] 20 Feb 2013, 09:50 ravitejar wrote: enigma123 wrote: The price of lunch for 15 people was$207 including a 15% gratuity for service. What was the average price per person, EXCLUDING the gratuity?

A. 11.73
B. 12
C. 13.8
D. 14
E. 15.87

How come the answer is B?

This is how I solved it and got A, which is incorrect.

$207 includes 15% gratuity so 0.15 * 207 = 31.05 Price EXCLUDING gratuity = 207 - 31.05 = 175.95 Average price per person = 175.95/15 = 11.73 I'll show You perhaps the most easiest way to solve such problem As it is a percentage problem so just take the initial price before the gratuity is 100 the as the gratuity is calculated on the final price, so as we assumed the final bill before adding gratuity is 100 so gratuity is 15% of 100 is 15 so the total price of meals is 115 so the given amount i.e 207 is for 115 then we have to calculate for 100 here we go for 115 207 for 100 x so by cross multiplication we get 115x=100*207 => x=100*207/110 by simplifying we get x as 180 which is the price of lunch before gratuity so the gratuity is 27 so as the question ask the average price person excluding gratuity is 180/15=12 so our answer is b hope its concise and clear . if u satisfied with my effort don't hesitate to give +1 kudos. Typical way to solve this nice _________________ I've failed over and over and over again in my life and that is why I succeed--Michael Jordan Kudos drives a person to better himself every single time. So Pls give it generously Wont give up till i hit a 700+ Manager Joined: 18 Oct 2011 Posts: 91 Location: United States Concentration: Entrepreneurship, Marketing GMAT Date: 01-30-2013 GPA: 3.3 Followers: 2 Kudos [?]: 28 [0], given: 0 Re: The price of lunch for 15 people was$207.00, including a 15 [#permalink]  20 Feb 2013, 13:14
let the price before gratuity = x
that means that (115/100)x = 207

Solving for x we get 180. 180/15 = 12. Answer B.
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Re: The price of lunch for 15 people was $207.00, including a 15 [#permalink] 27 Feb 2013, 20:31 Can someone please explain how you compute 207/1.15 under two minutes quickly? I think my division need help _________________ If my post has contributed to your learning or teaching in any way, feel free to hit the kudos button ^_^ Math Expert Joined: 02 Sep 2009 Posts: 25308 Followers: 3915 Kudos [?]: 34964 [2] , given: 4063 Re: The price of lunch for 15 people was$207.00, including a 15 [#permalink]  28 Feb 2013, 00:50
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DelSingh wrote:
Can someone please explain how you compute 207/1.15 under two minutes quickly? I think my division need help

Transform decimal into fraction: 1.15=1\frac{15}{100}=1\frac{3}{20}=\frac{23}{20}.

Bill*1.15=207 --> Bill*\frac{23}{20}=207 --> Bill*\frac{23}{20}=9*23 --> \frac{Bill}{20}=9 --> Bill=180.

Hope it helps.
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Re: The price of lunch for 15 people was $207.00, including a 15 [#permalink] 07 May 2014, 14:06 For those who are intimidated by the division I found back solving to be very efficient for this problem. I started with D$14.00

14*15 = 210 210>207 and that doesn't even have the gratuity added.

So I know right there that D and E are out and a 20 cent deduction on choice C is probably still going to be too high.

Went to answer choice B. $12.00 12*15=180 15% of 180=27 180+72=207.00 Intern Joined: 12 May 2014 Posts: 2 Followers: 0 Kudos [?]: 0 [0], given: 0 The price of lunch for 15 people was$207 including a 15% [#permalink]  12 May 2014, 01:55
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The price of lunch for 15 people was $207 including a 15% gratuity for service. What was the average price per person, EXCLUDING the gratuity? A. 11.73 B. 12 C. 13.8 D. 14 E. 15.87 here is my trouble: the answer is B, because people say that the "15%" means 15% of the real amount, by say real amount, I mean the amounts these guys paid for what they ate. but what puzzled me is that, the subject of the sentence is "the price", which equals to$207, so, in my opinion, the following "15%" is to modify "the price", which is $207. if so, the gratuity must be$207*15%, and in this way, answer is A.

so could anybody explain this to me? am i wrong?
thanks a lot!
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Re: The price of lunch for 15 people was $207 including a 15% [#permalink] 12 May 2014, 02:00 Expert's post MY42 wrote: The price of lunch for 15 people was$207 including a 15% gratuity for service. What was the average price per person, EXCLUDING the gratuity?

A. 11.73
B. 12
C. 13.8
D. 14
E. 15.87

here is my trouble:

the answer is B, because people say that the "15%" means 15% of the real amount, by say real amount, I mean the amounts these guys paid for what they ate.
but what puzzled me is that,
the subject of the sentence is "the price", which equals to $207, so, in my opinion, the following "15%" is to modify "the price", which is$207. if so, the gratuity must be $207*15%, and in this way, answer is A. so could anybody explain this to me? am i wrong? thanks a lot! Merging similar topics. please refer to the discussion above. As for your question, I think it's addressed here: the-price-of-lunch-for-15-people-was-207-00-including-a-131794.html#p1081531 Hope it helps. _________________ Intern Joined: 25 Jul 2014 Posts: 20 Concentration: Finance, General Management GPA: 3.54 WE: Asset Management (Venture Capital) Followers: 0 Kudos [?]: 10 [0], given: 52 The price of lunch for 15 people was$207.00, including a 15 [#permalink]  24 Aug 2014, 14:04
DelSingh wrote:
Can someone please explain how you compute 207/1.15 under two minutes quickly? I think my division need help

I TOTALLY agree with you. The problem is easy except for the 207/1.15 (well, the division is not hard, just time consuming). I got the right answer in 2:12, so my concern is also how to perform the division in 30 seconds?

Here is my thought (after thinking again and again )

First, 207/1.15 would be alot easier if it become 230/1.15 = 200, so the actual result will be less than 200... but how much less??
Then I think, i need to add 23 more from 207 to get 230, so it would be a little bit less than 23 from 200 since we divide the number to 1.15 (a little more than1)... my best guess is 20 (just because it's a round number), so the result is 180.

Not sure if it works in another problem with different numbers. I will keep this in mind for my next try.
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Re: The price of lunch for 15 people was $207.00, including a 15 [#permalink] 12 Sep 2014, 05:42 enigma123 wrote: The price of lunch for 15 people was$207.00, including a 15 percent gratuity for service. What was the average price per person, EXCLUDING the gratuity?

(A) $11.73 (B)$12.00
(C) $13.80 (D)$14.00
(E) $15.87 [Reveal] Spoiler: How come the answer is B? This is how I solved it and got A, which is incorrect.$207 includes 15% gratuity so 0.15 * 207 = 31.05

Price EXCLUDING gratuity = 207 - 31.05 = 175.95

Average price per person = 175.95/15 = 11.73

let x be the total without gratuity.. then we shall form

x+0.15x = 207
1.15x=207
x=207/1.15

x=180.

x/15 for each person then 180/15 = 12..
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The price of lunch for 15 people was $207.00, including a 15 [#permalink] 30 Oct 2014, 23:34 Per head without gratuity = \frac{207 * 100}{115 * 15} = \frac{900}{75} = 12 Answer = B _________________ Kindly press "+1 Kudos" to appreciate Intern Joined: 19 Jun 2014 Posts: 24 Location: Hungary Concentration: Finance, Accounting Schools: Erasmus '16 GMAT 1: Q V GPA: 4 WE: Corporate Finance (Energy and Utilities) Followers: 0 Kudos [?]: 6 [0], given: 4 Re: The price of lunch for 15 people was$207.00, including a 15 [#permalink]  07 Jan 2015, 12:19
The price included a gratuity of 15% on top of the original bill, hence $207.00 represents 115% of bill$x.yz

$207.00 ------- 115%$x.yz ---------- 100%

x = $180.00 Bill per person:$180.00 : 15 = $12.00 _________________ GMATPrep 1: 410 Q26 V20 (20 and 19 incorrect) GMATPrep 2: 620 Q44 V32 (12 and 14 incorrect) GMATPrep 3: 690 Q48 V37 (12 and 12 incorrect) Most important lessons learned so far: 1) Your first prep is NOT indicative of your true level. 2) First 10 questions ARE important (notice that between preps 2 and 3 I had only 2 less incorrect questions on Quant, but a 70 point total score difference) Re: The price of lunch for 15 people was$207.00, including a 15   [#permalink] 07 Jan 2015, 12:19
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