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

It is currently 18 Oct 2019, 04:12

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

In a certain class, x students are 10 years old, and the remaining y s

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

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58458
In a certain class, x students are 10 years old, and the remaining y s  [#permalink]

Show Tags

New post 23 Oct 2018, 21:59
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

82% (00:43) correct 18% (01:15) wrong based on 39 sessions

HideShow timer Statistics

In a certain class, x students are 10 years old, and the remaining y students are 11 years old. What is the average (arithmetic mean) age of all students in the class?


A. \(\frac{x+y}{21}\)

B. \(\frac{10x+11y}{21}\)

C. \(\frac{110xy}{x+y}\)

D. \(\frac{110xy}{xy}\)

E. \(\frac{10x+11y}{x+y}\)

_________________
Senior Manager
Senior Manager
User avatar
P
Joined: 13 Jan 2018
Posts: 342
Location: India
Concentration: Operations, General Management
GMAT 1: 580 Q47 V23
GMAT 2: 640 Q49 V27
GPA: 4
WE: Consulting (Consulting)
Reviews Badge
Re: In a certain class, x students are 10 years old, and the remaining y s  [#permalink]

Show Tags

New post 23 Oct 2018, 22:58
Total number of students is x+y

No if students of 10 years old is x. So total age of x students is 10x

No if students of 11 years old is y. So total age of y students is 11y.

Now average is \(\frac{10x+11y}{x+y}\)
_________________
____________________________
Regards,

Chaitanya


+1 Kudos

if you like my explanation!!!
Board of Directors
User avatar
D
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4771
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)
GMAT ToolKit User
In a certain class, x students are 10 years old, and the remaining y s  [#permalink]

Show Tags

New post 23 Oct 2018, 23:21
Bunuel wrote:
In a certain class, x students are 10 years old, and the remaining y students are 11 years old. What is the average (arithmetic mean) age of all students in the class?


A. \(\frac{x+y}{21}\)

B. \(\frac{10x+11y}{21}\)

C. \(\frac{110xy}{x+y}\)

D. \(\frac{110xy}{xy}\)

E. \(\frac{10x+11y}{x+y}\)


\(Average \ Age = \frac{Total \ Age \ of \ x \ students + Total \ Age \ of \ y \ students}{Total \ No \ of \ Students}\)

\(Average \ Age = \frac{10x + 11y}{(x + y )}\); Answer must be (E)
_________________
Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )
e-GMAT Representative
User avatar
V
Joined: 04 Jan 2015
Posts: 3074
Re: In a certain class, x students are 10 years old, and the remaining y s  [#permalink]

Show Tags

New post 24 Oct 2018, 03:53

Solution


Given:
    • x students are 10 years old
    • Remaining, y, students are 11 years old

To find:
    • The average age of all students in the class

Approach and Working:
    • Total number of students in the class = x + y
    • Sum of ages of x students = 10x
    • Sum of ages of remaining , y, students = 11y
    • Sum of ages of all the students in the class = 10x + 11y
    • Thus, Average age of all students = \(\frac{(10x + 11y)}{(x + y)}\)

Hence the correct answer is E

Answer: E

Image

_________________
GMAT Club Bot
Re: In a certain class, x students are 10 years old, and the remaining y s   [#permalink] 24 Oct 2018, 03:53
Display posts from previous: Sort by

In a certain class, x students are 10 years old, and the remaining y s

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





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