A students average (arithmetic mean) test score on 4 tests : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 17 Jan 2017, 01:42

### 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

# A students average (arithmetic mean) test score on 4 tests

Author Message
TAGS:

### Hide Tags

Intern
Joined: 08 Nov 2008
Posts: 29
Followers: 0

Kudos [?]: 32 [0], given: 0

A students average (arithmetic mean) test score on 4 tests [#permalink]

### Show Tags

11 Nov 2008, 12:33
1
This post was
BOOKMARKED
00:00

Difficulty:

5% (low)

Question Stats:

93% (01:23) correct 7% (00:15) wrong based on 115 sessions

### HideShow timer Statistics

A student's average (arithmetic mean) test score on 4 tests is 78. What must be the student's score on a 5th test for the student's average score on the 5 tests to be 80?

(A) 80
(B) 82
(C) 84
(D) 86
(E) 88

OPEN DISCUSSION OF THIS QUESTION IS HERE: a-student-s-average-arithmetic-mean-test-score-on-4-tests-137873.html
[Reveal] Spoiler: OA
SVP
Joined: 30 Apr 2008
Posts: 1887
Location: Oklahoma City
Schools: Hard Knocks
Followers: 40

Kudos [?]: 570 [3] , given: 32

### Show Tags

11 Nov 2008, 12:39
3
KUDOS
E. 88

The student must score at least an 80 for sure. If he scores an 8, then he will need to score 2 pots for each of the 4 other tests to "make up" the difference. They each were at 78 (at least the average is, but this is a small point and doesn't matter to the answer). So 4 tests that were each 2 points short of the 80 average that is desired means the next test must be 8 points higher than the desired average, so 80+8 = 88.

petercao wrote:
A student’s average (arithmetic mean) test score on 4 tests is 78. What must be the student’s score on a 5th test for the student’s average score on the 5 tests to be 80?

A. 80
B. 82
C. 84
D. 86
E. 88

_________________

------------------------------------
J Allen Morris
**I'm pretty sure I'm right, but then again, I'm just a guy with his head up his a.

GMAT Club Premium Membership - big benefits and savings

Manager
Joined: 02 Nov 2009
Posts: 138
Followers: 3

Kudos [?]: 165 [1] , given: 97

### Show Tags

26 Feb 2011, 21:35
1
KUDOS
Step 1) Total -= Average* number

total = 78*4 =312

Step 2) T = A*N
4th test + 5th = total
312 +5th test = (80*5)
5th test = 400-312 =88

testing on Total = A*n
Manager
Joined: 17 Jan 2011
Posts: 231
Followers: 1

Kudos [?]: 36 [0], given: 4

### Show Tags

09 Apr 2011, 14:43
avg on 4 is 78, in order to increase the avg to 80, the new number should be able to contribute 2 to each of the existing 4 numbers i.e. 8 in total so 88.
_________________

Good Luck!!!

***Help and be helped!!!****

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13421
Followers: 575

Kudos [?]: 163 [0], given: 0

Re: A students average (arithmetic mean) test score on 4 tests [#permalink]

### Show Tags

13 Sep 2013, 06:52
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Math Expert
Joined: 02 Sep 2009
Posts: 36530
Followers: 7068

Kudos [?]: 92947 [0], given: 10541

Re: A students average (arithmetic mean) test score on 4 tests [#permalink]

### Show Tags

13 Sep 2013, 07:52
A student's average (arithmetic mean) test score on 4 tests is 78. What must be the student's score on a 5th test for the student's average score on the 5 tests to be 80?

(A) 80
(B) 82
(C) 84
(D) 86
(E) 88

Since the student's average test score on 4 tests is 78, then the sum of the first 4 test scores is 4*78=312. We need the sum of ALL 5 scores to be 5*80=400, so if $$x$$ is the 5th test score, then $$312+x=400$$ --> $$x=88$$.

OPEN DISCUSSION OF THIS QUESTION IS HERE: a-student-s-average-arithmetic-mean-test-score-on-4-tests-137873.html
_________________
Re: A students average (arithmetic mean) test score on 4 tests   [#permalink] 13 Sep 2013, 07:52
Similar topics Replies Last post
Similar
Topics:
5 The average (arithmetic mean) score on a test taken by 10 students was 3 15 Jun 2016, 00:18
1 Joe’s average (arithmetic mean) test score across 4 equally weighted 3 07 Feb 2016, 09:56
1 Jerry’s average (arithmetic mean) score on the first 3 of 4 tests is 8 5 27 Dec 2015, 08:12
13 20 students took the test. The arithmetic mean of the scores 5 04 Aug 2013, 03:00
12 A student's average (arithmetic mean) test score on 4 tests 17 26 Aug 2012, 02:07
Display posts from previous: Sort by