Last visit was: 21 Apr 2026, 17:48 It is currently 21 Apr 2026, 17:48
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
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 21 Apr 2026
Posts: 109,728
Own Kudos:
Given Kudos: 105,800
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,728
Kudos: 810,468
 [18]
1
Kudos
Add Kudos
17
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 21 Apr 2026
Posts: 109,728
Own Kudos:
Given Kudos: 105,800
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,728
Kudos: 810,468
 [11]
5
Kudos
Add Kudos
5
Bookmarks
Bookmark this Post
avatar
takeTWO
Joined: 20 Oct 2013
Last visit: 28 Aug 2015
Posts: 4
Own Kudos:
17
 [5]
Given Kudos: 10
GMAT 1: 590 Q42 V29
WE:Information Technology (Consulting)
GMAT 1: 590 Q42 V29
Posts: 4
Kudos: 17
 [5]
3
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
General Discussion
avatar
Channarong22
Joined: 09 Mar 2016
Last visit: 17 Jun 2016
Posts: 2
Own Kudos:
1
 [1]
Given Kudos: 1
Posts: 2
Kudos: 1
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I think this is a high-quality question and I agree with explanation.
User avatar
TheNightKing
Joined: 18 Dec 2017
Last visit: 20 Mar 2024
Posts: 1,125
Own Kudos:
1,381
 [1]
Given Kudos: 421
Location: United States (KS)
GMAT 1: 600 Q46 V27
GMAT 1: 600 Q46 V27
Posts: 1,125
Kudos: 1,381
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
For the past \(k\) days the average (arithmetic mean) number of cupcakes baked by Liv was 55 per day. Today Bibi helped Liv and together they baked 100 cupcakes, which raised the average to 60 cupcakes per day. What is the value of \(k\)?

A. 8
B. 9
C. 10
D. 12
E. 13


All we care about is the increase.

So when they baked together the average went up to 60. So that means for last day 60 will be counted towards the average. Subtract that and you get 40.

Now 40 was used to increase average from 55 to 60. That means increase of 5. How many times you can distribute 5 out of 40? 8 times.

Answer A.
User avatar
monikakumar
Joined: 23 Jan 2020
Last visit: 31 Dec 2021
Posts: 234
Own Kudos:
Given Kudos: 467
Products:
Posts: 234
Kudos: 146
Kudos
Add Kudos
Bookmarks
Bookmark this Post
very well explained, i got this question wrong in gmat club test, thought as work/rate problem, then realized averaging.
User avatar
BottomJee
User avatar
Retired Moderator
Joined: 05 May 2019
Last visit: 09 Jun 2025
Posts: 994
Own Kudos:
Given Kudos: 1,009
Affiliations: GMAT Club
Location: India
GMAT Focus 1: 645 Q82 V81 DI82
GMAT 1: 430 Q31 V19
GMAT 2: 570 Q44 V25
GMAT 3: 660 Q48 V33
GPA: 3.26
WE:Engineering (Manufacturing)
Products:
GMAT Focus 1: 645 Q82 V81 DI82
GMAT 3: 660 Q48 V33
Posts: 994
Kudos: 1,456
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I think this is a high-quality question and I agree with explanation.
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 21 Apr 2026
Posts: 109,728
Own Kudos:
Given Kudos: 105,800
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,728
Kudos: 810,468
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I have edited the question and the solution by adding more details to enhance its clarity. I hope it is now easier to understand.
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,956
Own Kudos:
Posts: 38,956
Kudos: 1,117
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Automated notice from GMAT Club BumpBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.
Moderators:
Math Expert
109728 posts
Founder
43149 posts