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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: 549 Location: United Kingdom Concentration: International Business, Strategy GMAT Date: 06-22-2012 GPA: 2.9 WE: Information Technology (Consulting) Followers: 10 Kudos [?]: 150 [1] , given: 216 The price of lunch for 15 people was$207.00, including a 15 [#permalink]  02 May 2012, 14:55
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Difficulty:

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Question Stats:

67% (02:27) correct 32% (01:20) wrong based on 179 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 Math Expert Joined: 02 Sep 2009 Posts: 16900 Followers: 2778 Kudos [?]: 17669 [3] , given: 2235 Re: Price of lunch [#permalink] 03 May 2012, 11:56 3 This post received KUDOS 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.

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Re: The price of lunch for 15 people was $207.00, including a 15 [#permalink] 28 Feb 2013, 00:50 2 This post received KUDOS Expert's post 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. _________________ Director Status: Joined: 24 Jul 2011 Posts: 507 GMAT 1: 780 Q51 V48 GRE 1: 1540 Q800 V740 Followers: 53 Kudos [?]: 220 [1] , given: 9 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) _________________ Free profile evaluation by top b-school alumni: email us at info@gyanone.com 1-on-1 GMAT coaching. High quality, low price, maximum flexibility: http://www.gyanone.com/1-on-1-gmat/ Premium Admissions Consulting and MBA application help: http://www.gyanone.com/mba-essay-editing/ ISB admissions help from top ISB alumni: http://www.gyanone.com/isb-admissions-essays/ Visit our blog: http://www.gyanone.com/blog Intern Joined: 13 Nov 2010 Posts: 42 Followers: 0 Kudos [?]: 11 [1] , given: 2 Re: The price of lunch for 15 people was$207 including a 15% [#permalink]  03 May 2012, 06:51
1
KUDOS
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.
Intern
Joined: 19 Dec 2011
Posts: 21
Followers: 0

Kudos [?]: 3 [1] , given: 37

The price of lunch for 15 people was $207.00, including a [#permalink] 25 Aug 2012, 11:33 1 This post received KUDOS check the option : 12 12 * 15 = 180 180 + [ 18 + 9 ] ( 15 % of 180) = 207 Manager Joined: 02 Jun 2011 Posts: 159 Followers: 1 Kudos [?]: 12 [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 ? Manager Joined: 17 Sep 2011 Posts: 210 Followers: 0 Kudos [?]: 14 [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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Intern
Joined: 05 Apr 2012
Posts: 43
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Kudos [?]: 8 [0], given: 12

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 Senior Manager Status: Prevent and prepare. Not repent and repair!! Joined: 13 Feb 2010 Posts: 277 Location: India Concentration: Technology, General Management GPA: 3.75 WE: Sales (Telecommunications) Followers: 8 Kudos [?]: 28 [0], given: 276 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
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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: 92
Location: United States
Concentration: Entrepreneurship, Marketing
GMAT Date: 01-30-2013
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Followers: 2

Kudos [?]: 17 [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. Manager Joined: 25 Jul 2012 Posts: 80 Location: United States Followers: 0 Kudos [?]: 8 [0], given: 137 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
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Re: The price of lunch for 15 people was $207.00, including a 15 [#permalink] 27 Feb 2013, 20:31 Similar topics Replies Last post Similar Topics: This is a fairly easy one, but ... The price of lunch for 1 07 Jul 2006, 17:06 The price of lunch for 15 people was$207 including a 15 2 13 Nov 2006, 14:23