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

 It is currently 18 Oct 2019, 21:46 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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.  There are two examinations rooms A and B. If 10 students are sent from

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

Hide Tags

SVP  V
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 1685
Location: India
Concentration: International Business, Operations
Schools: INSEAD Jan '19
GPA: 3.01
WE: Engineering (Real Estate)
There are two examinations rooms A and B. If 10 students are sent from  [#permalink]

Show Tags

6 00:00

Difficulty:   45% (medium)

Question Stats: 67% (02:28) correct 33% (02:16) wrong based on 81 sessions

HideShow timer Statistics

There are two examinations rooms A and B. If 10 students are sent from A to B, then the number of students in each room is the same. If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B. The number of students in room A is

a. 20

b. 80

c. 100

d. 150

e. 200

_________________
"Do not watch clock; Do what it does. KEEP GOING."
Math Expert V
Joined: 02 Aug 2009
Posts: 7981
Re: There are two examinations rooms A and B. If 10 students are sent from  [#permalink]

Show Tags

1
1
AkshdeepS wrote:
There are two examinations rooms A and B. If 10 students are sent from A to B, then the number of students in each room is the same. If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B. The number of students in room A is

a. 20

b. 80

c. 100

d. 150

e. 200

If 10 students are sent from A to B, then the number of students in each room is the same MEANS A=B+20, (as A-10=B+10)
If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B. MEANS 2(B-20)=A+20. Substitute A as B+20..
=> 2B-40=B+20+20...B=80, so A=B+20=80+20=100..

OR

We can work from choices..

a. 20.... so B=0...Not possible

b. 80...... so B=60.. When 20 are given from B : B=40 and A=100...NO

c. 100...... so B=80.. When 20 are given from B : B=60 and A=120... YES 120 =2*60

C
_________________
GMAT Club Legend  D
Joined: 18 Aug 2017
Posts: 5020
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: There are two examinations rooms A and B. If 10 students are sent from  [#permalink]

Show Tags

1
AkshdeepS wrote:
There are two examinations rooms A and B. If 10 students are sent from A to B, then the number of students in each room is the same. If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B. The number of students in room A is

a. 20

b. 80

c. 100

d. 150

e. 200

AkshdeepS why is this question being tagged as 700?

solution is <30 secs
let students A = x and class B = y
we need to find value of x
case 1 ; x-10=y-10
so y = x-20-- ( a)

case 2; x+20= 2*(y-20)
x+20 = 2y-40
substitute value of y from (a)
we get
x+20= 2*(x-20)-40
x+20=2x-40-40
or say x= 100
IMO C SVP  V
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 1685
Location: India
Concentration: International Business, Operations
Schools: INSEAD Jan '19
GPA: 3.01
WE: Engineering (Real Estate)
There are two examinations rooms A and B. If 10 students are sent from  [#permalink]

Show Tags

Archit3110 wrote:
AkshdeepS wrote:
There are two examinations rooms A and B. If 10 students are sent from A to B, then the number of students in each room is the same. If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B. The number of students in room A is

a. 20

b. 80

c. 100

d. 150

e. 200

AkshdeepS why is this question being tagged as 700?

solution is <30 secs
let students A = x and class B = y
we need to find value of x
case 1 ; x-10=y-10
so y = x-20-- ( a)

case 2; x+20= 2*(y-20)
x+20 = 2y-40
substitute value of y from (a)
we get
x+20= 2*(x-20)-40
x+20=2x-40-40
or say x= 100
IMO C Archit3110 : Stats of the question are also saying a 700+ level .
Please think of people like me who are struggling in quant. _________________
"Do not watch clock; Do what it does. KEEP GOING."
GMAT Club Legend  D
Joined: 18 Aug 2017
Posts: 5020
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: There are two examinations rooms A and B. If 10 students are sent from  [#permalink]

Show Tags

AkshdeepS ; kind apologize but i did not mean to comment upon anyones skill or current preparation level, even I myself is sailing on the same boat called "GMAT" ,  well all I felt was that the question was of medium difficulty nevertheless until a question is relevant to gmat , it is then a good question to practise ..
keep posting such good questions.. AkshdeepS wrote:
Archit3110 wrote:
AkshdeepS wrote:
There are two examinations rooms A and B. If 10 students are sent from A to B, then the number of students in each room is the same. If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B. The number of students in room A is

a. 20

b. 80

c. 100

d. 150

e. 200

AkshdeepS why is this question being tagged as 700?

solution is <30 secs
let students A = x and class B = y
we need to find value of x
case 1 ; x-10=y-10
so y = x-20-- ( a)

case 2; x+20= 2*(y-20)
x+20 = 2y-40
substitute value of y from (a)
we get
x+20= 2*(x-20)-40
x+20=2x-40-40
or say x= 100
IMO C Stats of the question is also saying a 700+ level .
Please think of people like me who are struggling in quant. SVP  V
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 1685
Location: India
Concentration: International Business, Operations
Schools: INSEAD Jan '19
GPA: 3.01
WE: Engineering (Real Estate)
There are two examinations rooms A and B. If 10 students are sent from  [#permalink]

Show Tags

Quote:
AkshdeepS ; kind apologize but i did not mean to comment upon anyones skill or current preparation level, even I myself is sailing on the same boat called "GMAT" ,  well all I felt was that the question was of medium difficulty nevertheless until a question is relevant to gmat , it is then a good question to practise ..
keep posting such good questions.. Archit3110 ; Not need to apologise bro as you said nothing sort of hurting. Neither you compared skills nor did you undermine anyone's. Good to have some lively chats and light moments, otherwise the GMAT journey is a pain that we expect to change in happiness sometime in future. We all are in the same boat till someone's profile shows a 700+ suddenly, and we think Ohh...one more left us behind.. Cheers: All the best.
_________________
"Do not watch clock; Do what it does. KEEP GOING."
GMAT Club Legend  D
Joined: 18 Aug 2017
Posts: 5020
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: There are two examinations rooms A and B. If 10 students are sent from  [#permalink]

Show Tags

AkshdeepS wrote:
Quote:
AkshdeepS ; kind apologize but i did not mean to comment upon anyones skill or current preparation level, even I myself is sailing on the same boat called "GMAT" ,  well all I felt was that the question was of medium difficulty nevertheless until a question is relevant to gmat , it is then a good question to practise ..
keep posting such good questions.. Archit3110 ; Not need to apologise bro as you said nothing sort of hurting. Neither you compared skills nor did you undermine anyone's. Good to have some lively chats and light moments, otherwise the GMAT journey is a pain that we expect to change in happiness sometime in future. We all are in the same boat till someone's profile shows a 700+ suddenly, and we think Ohh...one more left us behind.. Cheers: All the best.

AkshdeepS .. thanks
Manager  S
Joined: 24 Nov 2018
Posts: 107
Location: India
GPA: 3.27
WE: General Management (Retail Banking)
Re: There are two examinations rooms A and B. If 10 students are sent from  [#permalink]

Show Tags

AkshdeepS wrote:
There are two examinations rooms A and B. If 10 students are sent from A to B, then the number of students in each room is the same. If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B. The number of students in room A is

a. 20

b. 80

c. 100

d. 150

e. 200

Let the number of students in room a and b = x and y.

Eqn. 1:-$$x-10=y+10$$
or $$x-y=20$$

Eqn2:-$$x+20=2(y-20)$$
or $$2y-x=60$$

Solve for x and y

$$x=100, y=80,$$ IMO, Option C.
_________________
Kudos encourage discussions. Share it to amplify collective education!
Manager  B
Joined: 17 Jun 2017
Posts: 60
Re: There are two examinations rooms A and B. If 10 students are sent from  [#permalink]

Show Tags

Archit3110 wrote:
AkshdeepS wrote:
There are two examinations rooms A and B. If 10 students are sent from A to B, then the number of students in each room is the same. If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B. The number of students in room A is

a. 20

b. 80

c. 100

d. 150

e. 200

AkshdeepS why is this question being tagged as 700?

solution is <30 secs
let students A = x and class B = y
we need to find value of x
case 1 ; x-10=y-10
so y = x-20-- ( a)

case 2; x+20= 2*(y-20)
x+20 = 2y-40
substitute value of y from (a)
we get
x+20= 2*(x-20)-40
x+20=2x-40-40
or say x= 100
IMO C Not everyone can be in the same shoes buddy ! Would request pundits not to judge.
Manager  S
Joined: 15 Jan 2018
Posts: 60
There are two examinations rooms A and B. If 10 students are sent from  [#permalink]

Show Tags

Another way to solve is to use the first condition as a qualifier for the second condition.

The first condition says, if 10 students are moved from A to B, then the class sizes are equal. This means that the difference in class sizes must be 20.

Now we must use the difference of 20 to qualify the answer choices for the second condition.
We will phrase this as can 2*(20 less than the number in B) = A+20?

In the following math, just remember that B is 20 less than A, which is how I get 0, 60, and 80.

A. Does 2(0-20) = (20+20)? No.

B. Does 2(60-20) = (80+20)? No.

C. Does 2(80-20) = (100+20)? Yes! Answer C There are two examinations rooms A and B. If 10 students are sent from   [#permalink] 15 Apr 2019, 16:42
Display posts from previous: Sort by

There are two examinations rooms A and B. If 10 students are sent from

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

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