GMAT Changed on April 16th - Read about the latest changes here

 It is currently 22 May 2018, 23:55

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# The average of 12 numbers 16. When one number is discarded and 15 is a

Author Message
TAGS:

### Hide Tags

Intern
Joined: 26 May 2017
Posts: 3
The average of 12 numbers 16. When one number is discarded and 15 is a [#permalink]

### Show Tags

Updated on: 19 Jun 2017, 10:48
2
KUDOS
1
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

76% (01:20) correct 24% (01:25) wrong based on 109 sessions

### HideShow timer Statistics

The average of 12 numbers 16. When one number is discarded and 15 is added, the average becomes 17. What is the number that is discarded?

A. 3
B. 5
C. 6
D. 10
E. 12

Originally posted by Antonio.Salazar2887 on 19 Jun 2017, 10:01.
Last edited by Bunuel on 19 Jun 2017, 10:48, edited 1 time in total.
Renamed the topic, edited the question and added the OA.
Intern
Joined: 20 Feb 2017
Posts: 15
Location: India
GMAT 1: 560 Q47 V21
GPA: 3.05
WE: Other (Entertainment and Sports)
Re: The average of 12 numbers 16. When one number is discarded and 15 is a [#permalink]

### Show Tags

19 Jun 2017, 10:19
A 3.

16*12 - x +15 = 17*12
192+15 -x = 204
207-204 = x
x = 3.
Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 3440
Location: India
GPA: 3.5
Re: The average of 12 numbers 16. When one number is discarded and 15 is a [#permalink]

### Show Tags

19 Jun 2017, 11:11
Antonio.Salazar2887 wrote:
The average of 12 numbers 16. When one number is discarded and 15 is added, the average becomes 17. What is the number that is discarded?

A. 3
B. 5
C. 6
D. 10
E. 12

$$\frac{12*16 - x + 15}{12} = 17$$

$$192 - x + 15 = 204$$

Or, $$x = 3$$

_________________

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 )

BSchool Forum Moderator
Joined: 26 Feb 2016
Posts: 2552
Location: India
GPA: 3.12
Re: The average of 12 numbers 16. When one number is discarded and 15 is a [#permalink]

### Show Tags

19 Jun 2017, 12:48
Given data : The average of 12 number is 16, and one of the numbers(x) is removed.

The number which replaces x is 15, and this makes the overall average go up to 17(an increase of 1)
x must be 12 lesser than 15 since the replacement of the number causes the average to go up 1.
Hence, x = 15-12 = 3(Option A)
_________________

You've got what it takes, but it will take everything you've got

SC Moderator
Joined: 22 May 2016
Posts: 1668
The average of 12 numbers 16. When one number is discarded and 15 is a [#permalink]

### Show Tags

19 Jun 2017, 13:42
Antonio.Salazar2887 wrote:
The average of 12 numbers 16. When one number is discarded and 15 is added, the average becomes 17. What is the number that is discarded?

A. 3
B. 5
C. 6
D. 10
E. 12

Using (Average * number of terms) = Sum

Find the sum of first set of numbers.

Find the sum of the second set of numbers.

Set up an equation where the first sum is changed per the prompt, and equals the second sum.

1. (A)*(n) = S (the number of terms, 12, does not change)

Sum of first set of numbers: 16 * 12 = 192

Sum of second set of numbers: 17 * 12 = 204 (RHS)

2. Equation. From the first sum of 192, some number, x, is subtracted, and 15 is added (LHS):

192 - x + 15 = 204
-x = -3, or
x = 3

_________________

In the depths of winter, I finally learned
that within me there lay an invincible summer.

Director
Joined: 04 Dec 2015
Posts: 700
Location: India
Concentration: Technology, Strategy
Schools: ISB '19, IIMA , IIMB, XLRI
WE: Information Technology (Consulting)
The average of 12 numbers 16. When one number is discarded and 15 is a [#permalink]

### Show Tags

19 Jun 2017, 18:11
1
KUDOS
Antonio.Salazar2887 wrote:
The average of 12 numbers 16. When one number is discarded and 15 is added, the average becomes 17. What is the number that is discarded?

A. 3
B. 5
C. 6
D. 10
E. 12

Average to 12 numbers $$= 16$$

Sum of 12 numbers $$= 16 * 12 = 192.$$ ---------- (i)

Average of 12 numbers (one number is discarded) and 15 is added $$= 17$$

Sum of 12 numbers (one number is discarded) and 15 is added $$= 17 * 12 = 204$$-------------- (ii)

Subtracting (ii) from (i), we get;

$$204 - 192 = 12$$

Difference between 15 and number discarded is 12. Let the number be x.

$$15 - x = 12$$

$$x = 15 - 12 = 3.$$

Hence the number discarded $$= 3.$$ Answer (A) ...
Manager
Joined: 27 Mar 2016
Posts: 52
Re: The average of 12 numbers 16. When one number is discarded and 15 is a [#permalink]

### Show Tags

19 Jun 2017, 20:39
Sum of 12 numbers=16*12=192
When one number is discarded and 15 is added then sum= 17*12=204
Let the number discarded be x
192-x+15=204
207-x=204
Hence x=3
A

Sent from my ONEPLUS A3003 using GMAT Club Forum mobile app
Verbal Forum Moderator
Joined: 19 Mar 2014
Posts: 974
Location: India
Concentration: Finance, Entrepreneurship
GPA: 3.5
Re: The average of 12 numbers 16. When one number is discarded and 15 is a [#permalink]

### Show Tags

24 Jun 2017, 15:48
$$Average = \frac{Sum}{Count}$$

$$12 = \frac{Sum}{16}$$

$$12 * 16 = Sum$$

$$Sum = 192$$

Now, we remove one number and add 15, and the new average is 17

$$12 = \frac{New Sum}{17}$$

$$12 * 17 = New Sum$$

$$New Sum = 204$$

So, difference between $$Sum$$ and $$New Sum = 204 - 192 = 12$$

As we have added 15, we will substract above number from $$15 = 15-12 = 3$$

_________________

"Nothing in this world can take the place of persistence. Talent will not: nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not: the world is full of educated derelicts. Persistence and determination alone are omnipotent."

Best AWA Template: https://gmatclub.com/forum/how-to-get-6-0-awa-my-guide-64327.html#p470475

Target Test Prep Representative
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2442
Re: The average of 12 numbers 16. When one number is discarded and 15 is a [#permalink]

### Show Tags

06 Jul 2017, 17:47
Antonio.Salazar2887 wrote:
The average of 12 numbers 16. When one number is discarded and 15 is added, the average becomes 17. What is the number that is discarded?

A. 3
B. 5
C. 6
D. 10
E. 12

Since the average of 12 numbers is 16, the sum of those numbers is 12 x 16 = 192.

We can let x = the discarded number and we can create the following equation:

(192 - x + 15)/12 = 17

207 - x = 204

x = 3

_________________

Jeffery Miller

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Senior Manager
Joined: 28 Jun 2015
Posts: 297
Concentration: Finance
GPA: 3.5
Re: The average of 12 numbers 16. When one number is discarded and 15 is a [#permalink]

### Show Tags

06 Jul 2017, 18:36
Sum of 12 numbers = $$12*16 = 192$$

Discarding a number (x, say) and adding 15, we get = $$\frac{192 - x + 15}{12} = 17$$

$$192 - x + 15 = 204$$

$$-x = 204 - 192 - 15$$

$$x = 3$$. Ans - A.
_________________

I used to think the brain was the most important organ. Then I thought, look what’s telling me that.

Re: The average of 12 numbers 16. When one number is discarded and 15 is a   [#permalink] 06 Jul 2017, 18:36
Display posts from previous: Sort by