NEW HERE? LEARN MORE
closeclose
Last visit was: 24 Apr 2024, 18:20 It is currently 24 Apr 2024, 18:20
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

Dave’s quiz scores are 60, 90, and 80. What is the score Dave would ne

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92900
Own Kudos [?]: 618818 [2]
Given Kudos: 81588
Send PM
CAT Tests Forum Quiz Mode
Dave’s quiz scores are 60, 90, and 80. What is the score Dave would ne [#permalink] New post   08 Jul 2021, 02:30
1
Kudos
1
Bookmarks
Expert Reply
00:00
A
B
C
D
E

Difficulty:

5% (low)

Question Stats:

91% (00:59) correct 9% (01:33) wrong based on 76 sessions
Hide Show timer Statistics
Dave’s quiz scores are 60, 90, and 80. What is the score Dave would need on his next quiz to increase his overall average score to 82?

A. 92
B. 94
C. 96
D. 98
E. 100
ShowHide Answer
Official Answer
D
Most Helpful Reply
User avatar
L
BrentGMATPrepNow
GMAT Club Legend
GMAT Club Legend
Joined: 12 Sep 2015
Posts: 6821
Own Kudos [?]: 29911 [1]
Given Kudos: 799
Location: Canada
Send PM
Dave’s quiz scores are 60, 90, and 80. What is the score Dave would ne [#permalink] New post   08 Jul 2021, 07:30
1
Kudos
Expert Reply
Top Contributor
Bunuel wrote:
Dave’s quiz scores are 60, 90, and 80. What is the score Dave would need on his next quiz to increase his overall average score to 82?

A. 92
B. 94
C. 96
D. 98
E. 100


After the next quiz, Dave will have taken 4 quizzes.
If the average of those 4 quizzes is 82, then it must be the case that: (sum of all 4 quizzes)/4 = 82
Multiply both sides of the equation by 4 to get: sum of all 4 quizzes = 328

If we let x = the required score on the fourth test, we can write: 60 + 90 + 80 + x = 328
Solve to get: x = 98

Answer: D
General Discussion
User avatar
L
GmatKnightTutor
GMAT Club Legend
GMAT Club Legend
Joined: 31 Jan 2020
Posts: 4413
Own Kudos [?]: 1304 [0]
Given Kudos: 16
Send PM
Dave’s quiz scores are 60, 90, and 80. What is the score Dave would ne [#permalink] New post   08 Jul 2021, 07:38
An interesting way to approach this is to note how each of the digits ends in a 0 - this means that the sum of the values will end in a 0. Why is this noteworthy? When you hear that the average of 4 numbers is 82, that is basically telling you 328 is the total of those numbers.

If the total equals 328
and the current sum of the 3 numbers ends in a 0

You need a number that ends in an 8.

(D)
avatar
B
sahuanamika
Intern
Intern
Joined: 22 May 2021
Posts: 49
Own Kudos [?]: 18 [0]
Given Kudos: 108
Send PM
Re: Dave’s quiz scores are 60, 90, and 80. What is the score Dave would ne [#permalink] New post   10 Jul 2021, 04:01
Dave’s quiz scores are 60, 90, and 80.
Now we can calculate the next score without using the average equation formulae :

If we say that average is 82 then , next score must add that much weightage to make it 82.
Consider a line segment

<--------------------------------------avg--------------------------------------->
60 80 82 90 x
we must add 60+ 22 = 82 (avg) --- 22 (1)
we must add 80 + 2 = 82 (avg) --- 2 (2)
we must dec 90 - 8 = 82 (avg) --- -8 (3)

so total 22+2- 8 = 16 we need to add to 82 ..add because here the sign is positive
so, 82(avg) + 16 = 98

Ans D
GMAT Club Bot
gmatclubot
Re: Dave’s quiz scores are 60, 90, and 80. What is the score Dave would ne [#permalink]
10 Jul 2021, 04:01
Moderators:
Bunuel
Math Expert
92900 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions