GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 22 Sep 2019, 03:59

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

If 75 percent of the guests at a certain banquet ordered dessert, what

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Intern
Intern
User avatar
B
Joined: 08 May 2016
Posts: 25
Location: United States
WE: Project Management (Aerospace and Defense)
Re: If 75 percent of the guests at a certain banquet ordered dessert, what  [#permalink]

Show Tags

New post Updated on: 28 Nov 2016, 09:43
ts30 wrote:
Bunuel wrote:
SOLUTION

If 75 percent of the guests at a certain banquet ordered dessert, what percent of the guests ordered coffee?

Assume there were 100 guests on the banquet. So we have that 75 of them ordered dessert.

(1) 60 percent of the guests who ordered dessert also ordered coffee --> 0.6*75=45 guests ordered both dessert AND coffee, but we still don't know how many guests ordered coffee. Not sufficient.

(2) 90 percent of the guests who ordered coffee also ordered dessert --> 0.9*(coffee) # of guests who ordered both dessert AND coffee. Not sufficient.

(1)+(2) From (1) # of guests who ordered both dessert AND coffee is 45 and from (2) 0.9*(coffee)=45 --> (coffee)=50. Sufficient.

Answer: C.


Are we assuming that there are only 2 things to order- Coffee and dessert and everyone made a choice from these 2 things only... Implying that the sum total of coffee and non-coffee takers = 100%?


I have the same doubt. Bunuel, how do we deduce that there isn't a category of people who haven't ordered anything?
Attachments

File comment: Bunuel, this attached file is my interpretation, although I'm still not clear on how the set of people who don't order coffee or dessert doesn't affect the solution
QR2-DS-116.PNG
QR2-DS-116.PNG [ 20.43 KiB | Viewed 2854 times ]


_________________
What's your totem?

Originally posted by herbgatherer on 27 Nov 2016, 18:01.
Last edited by herbgatherer on 28 Nov 2016, 09:43, edited 1 time in total.
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58095
Re: If 75 percent of the guests at a certain banquet ordered dessert, what  [#permalink]

Show Tags

New post 28 Nov 2016, 01:34
1
herbgatherer wrote:
ts30 wrote:
Bunuel wrote:
SOLUTION

If 75 percent of the guests at a certain banquet ordered dessert, what percent of the guests ordered coffee?

Assume there were 100 guests on the banquet. So we have that 75 of them ordered dessert.

(1) 60 percent of the guests who ordered dessert also ordered coffee --> 0.6*75=45 guests ordered both dessert AND coffee, but we still don't know how many guests ordered coffee. Not sufficient.

(2) 90 percent of the guests who ordered coffee also ordered dessert --> 0.9*(coffee) # of guests who ordered both dessert AND coffee. Not sufficient.

(1)+(2) From (1) # of guests who ordered both dessert AND coffee is 45 and from (2) 0.9*(coffee)=45 --> (coffee)=50. Sufficient.

Answer: C.


Are we assuming that there are only 2 things to order- Coffee and dessert and everyone made a choice from these 2 things only... Implying that the sum total of coffee and non-coffee takers = 100%?


I have the same doubt. Bunuel, how do we deduce that there isn't a category of people who haven't ordered anything?


We are not assuming that but the number of people who ordered neither coffee or desert does not play any part in the solution.
_________________
Senior Manager
Senior Manager
User avatar
P
Joined: 10 Apr 2018
Posts: 271
Location: United States (NC)
Re: If 75 percent of the guests at a certain banquet ordered dessert, what  [#permalink]

Show Tags

New post 14 Aug 2018, 17:08
Lets say there are total 100 Guests. We are told 75 ordered Deseret, and we have to calculate % of people who ordered coffee
So what we need is no of people who ordered coffee which is no of people who ordered only coffee and and number of people who ordered both coffee and desert.

Stmt 1: Tells us no of people who ordered both = 45, So if 45 ordered both then only 30 ordered only desert. but we have no information on no of people who ordered only coffee and no of people who ordered none.

Stmt 2: 90 % of those who ordered coffee also ordered desert. Since we don't have the values of those who ordered coffee or those who ordered coffee and desert we cant calculate any thing from this information.

Now we already know from second statement if we have information about no of people ordering both we can calculate no of people who ordered coffee.

So combining Stmt 1 and Stmt 2, We have
90% of x= 45, so x =50, this is number of people who ordered coffee. So we can calculate the required % which is about 50 %
So Only Desert 30, Desert & Coffee 45, Only Coffee 5, 20 none , which gives total 100.

Probus
_________________
Probus

~You Just Can't beat the person who never gives up~ Babe Ruth
Manager
Manager
User avatar
S
Status: Don't Give Up!
Joined: 15 Aug 2014
Posts: 95
Location: India
Concentration: Operations, General Management
GMAT Date: 04-25-2015
WE: Engineering (Manufacturing)
CAT Tests
Re: If 75 percent of the guests at a certain banquet ordered dessert, what  [#permalink]

Show Tags

New post 30 Apr 2019, 01:24
VeritasKarishma wrote:
Baten80 wrote:
IF 75% of guest at a certain banquet ordered dessert,what percent of guest ordered coffee?

1)60%of the guest who ordered dessert also ordered coffee.

2)90%of the guest who ordered coffee also ordered dessert.


In questions involving sets, venn diagrams can be used. They tend to make questions simple.

We need to find the % of total guests (G) who ordered coffee (C). So we want C in terms of G.
Given D = 75% of G

1. 60% of D ordered coffee too
Attachment:
Ques1.jpg

From the diagram, we see that we do not know what % people ordered only coffee.

2. 90% of C ordered Dessert too.
Attachment:
Ques2.jpg

From the diagram, we see that we do not know what % people ordered only coffee.

Using both the statements, we see that
60% * 75% * G = 90% * C
Since we get C in terms of G, this is sufficient. Answer (C)


Thanks for the explanation....I think to assume there is neither Dessert nor coffee case exist would help in solving the problem...Sometimes assuming total = 100 and then dividing them to different groups makes you to forget that neither case.... Whether my thought process correct?
_________________
- Sachin

-If you like my explanation then please click "Kudos"
Manager
Manager
avatar
B
Joined: 29 Sep 2016
Posts: 112
Re: If 75 percent of the guests at a certain banquet ordered dessert, what  [#permalink]

Show Tags

New post 25 Aug 2019, 02:46
Bunuel wrote:
SOLUTION

If 75 percent of the guests at a certain banquet ordered dessert, what percent of the guests ordered coffee?

Assume there were 100 guests on the banquet. So we have that 75 of them ordered dessert.

(1) 60 percent of the guests who ordered dessert also ordered coffee --> 0.6*75=45 guests ordered both dessert AND coffee, but we still don't know how many guests ordered coffee. Not sufficient.

(2) 90 percent of the guests who ordered coffee also ordered dessert --> 0.9*(coffee) # of guests who ordered both dessert AND coffee. Not sufficient.

(1)+(2) From (1) # of guests who ordered both dessert AND coffee is 45 and from (2) 0.9*(coffee)=45 --> (coffee)=50. Sufficient.

Answer: C.


Hi Bunuel
Can we assume that there wasn't any other edible item ?
GMAT Club Bot
Re: If 75 percent of the guests at a certain banquet ordered dessert, what   [#permalink] 25 Aug 2019, 02:46

Go to page   Previous    1   2   [ 25 posts ] 

Display posts from previous: Sort by

If 75 percent of the guests at a certain banquet ordered dessert, what

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne