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

 It is currently 19 Oct 2019, 02:50

### 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

# 30 students had an average of X, while 20 students had an average of

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 58452

### Show Tags

01 Mar 2018, 00:39
00:00

Difficulty:

25% (medium)

Question Stats:

83% (01:26) correct 17% (01:13) wrong based on 34 sessions

### HideShow timer Statistics

30 students had an average of X, while 20 students had an average of 80. What is the average for the entire group?

(A) (X + 80)/50
(B) (X + 80)/2
(C) 50/(X + 80)
(D) 3X/5 + 32
(E) (30X + 80)/50

_________________
examPAL Representative
Joined: 07 Dec 2017
Posts: 1153

### Show Tags

01 Mar 2018, 00:52
Bunuel wrote:
30 students had an average of X, while 20 students had an average of 80. What is the average for the entire group?

(A) (X + 80)/50
(B) (X + 80)/2
(C) 50/(X + 80)
(D) 3X/5 + 32
(E) (30X + 80)/50

Instead of calculating, we'll pick an easy number for X.
This is an Alternative appraoch.

Say X = 80.
Then all students had an average of 80 so the total average must also be 80.
(A) is not 80.
(B) is 80. Maybe. Let's check the others.
(C) is not 80.
(D) is 240/5 + 32 = 48 + 32 = 80.
(E) is (3*80+8)/5 = 248/5 which is not 80.

So our answer is (B) or (D).
Let's now try X = 0. Then the average is (20*80)/50 = 160/5 = 32
(B) is 40. No!
(D) is 0 + 32 = 32 and is our answer.

_________________
VP
Joined: 31 Oct 2013
Posts: 1465
Concentration: Accounting, Finance
GPA: 3.68
WE: Analyst (Accounting)

### Show Tags

01 Mar 2018, 03:39
Bunuel wrote:
30 students had an average of X, while 20 students had an average of 80. What is the average for the entire group?

(A) (X + 80)/50
(B) (X + 80)/2
(C) 50/(X + 80)
(D) 3X/5 + 32
(E) (30X + 80)/50

we are looking for the average of the entire group.
first of all i want to dig up a issue that our total student is 30+20=50

now , total no. of 30 students is 30x
total no. of 20 students is 20*80=1600

average of 50 students = 30x+1600/50
= 30x/50+1600/50
=3x/5+32
so, option D is our correct answer. hope it helps u.
Intern
Joined: 19 Feb 2018
Posts: 5

### Show Tags

01 Mar 2018, 05:45
To find the average score,
total score for 30 students is 30x
Total score for 20 students is (20*80=1600)
Average score for group(30+20=50)
is (30x + 1600)/50
That is
(3x/5)+32

Option D

Sent from my [device_name] using [url]GMAT Club Forum mobile app[/url]
Intern
Joined: 19 Feb 2018
Posts: 5

### Show Tags

01 Mar 2018, 05:46
selim wrote:
Bunuel wrote:
30 students had an average of X, while 20 students had an average of 80. What is the average for the entire group?

(A) (X + 80)/50
(B) (X + 80)/2
(C) 50/(X + 80)
(D) 3X/5 + 32
(E) (30X + 80)/50

we are looking for the average of the entire group.
first of all i want to dig up a issue that our total student is 30+20=50

now , total no. of 30 students is 30x
total no. of 20 students is 20*80=1600

average of 50 students = 30x+1600/50
= 30x/50+1600/50
=3x/5+32
so, option D is our correct answer. hope it helps u.
U have to calculate sir... Cos of time

Sent from my [device_name] using [url]GMAT Club Forum mobile app[/url]
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8109
Location: United States (CA)

### Show Tags

02 Mar 2018, 10:35
Bunuel wrote:
30 students had an average of X, while 20 students had an average of 80. What is the average for the entire group?

(A) (X + 80)/50
(B) (X + 80)/2
(C) 50/(X + 80)
(D) 3X/5 + 32
(E) (30X + 80)/50

The average for the entire group is:

(30X + 20(80))/50 = (30X + 1600)/50 = 30X/50 + 1600/50 = 3X/5 + 32

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Director
Joined: 21 May 2013
Posts: 636

### Show Tags

02 Mar 2018, 10:57
Bunuel wrote:
30 students had an average of X, while 20 students had an average of 80. What is the average for the entire group?

(A) (X + 80)/50
(B) (X + 80)/2
(C) 50/(X + 80)
(D) 3X/5 + 32
(E) (30X + 80)/50

Average of the entire group= 30X+1600/(30+20)=30X+1600/50=3X/5+32
Re: 30 students had an average of X, while 20 students had an average of   [#permalink] 02 Mar 2018, 10:57
Display posts from previous: Sort by