Last visit was: 21 Apr 2026, 14:06 It is currently 21 Apr 2026, 14:06
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: 109,727
Own Kudos:
810,460
 [4]
Given Kudos: 105,799
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,727
Kudos: 810,460
 [4]
Kudos
Add Kudos
4
Bookmarks
Bookmark this Post
avatar
itsanujsingh
Joined: 27 Sep 2018
Last visit: 09 Jan 2022
Posts: 30
Own Kudos:
41
 [2]
Given Kudos: 14
Posts: 30
Kudos: 41
 [2]
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
User avatar
Archit3110
User avatar
Major Poster
Joined: 18 Aug 2017
Last visit: 21 Apr 2026
Posts: 8,626
Own Kudos:
Given Kudos: 243
Status:You learn more from failure than from success.
Location: India
Concentration: Sustainability, Marketing
GMAT Focus 1: 545 Q79 V79 DI73
GMAT Focus 2: 645 Q83 V82 DI81
GPA: 4
WE:Marketing (Energy)
Products:
GMAT Focus 2: 645 Q83 V82 DI81
Posts: 8,626
Kudos: 5,190
Kudos
Add Kudos
Bookmarks
Bookmark this Post
avatar
GMathGuy
Joined: 25 Mar 2019
Last visit: 06 Sep 2022
Posts: 2
Own Kudos:
4
 [2]
Given Kudos: 7
Posts: 2
Kudos: 4
 [2]
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
We know the Total is sum of boys and girls. However, since 40% are girls - we have a ratio given of boys to girls = 60 : 40 = 6 : 4
(for ease of calculation, I would not simplify the ratio to 3:2) --->
Number of boys = 6X
Number of girls = 4X

It is important to use X because while 6:4 is a ratio, 6X and 4X are absolute values that we do not know yet.

Two girls leave, so number of girls (new) = 4X - 2
Two boys added, so number of boys (new) = 6X + 2

The ratio between these two new values = (4X-2)/(6X+2) ---> which is given to be equal to 30/70.
Solve (4X-2)/(6X+2) = 3/7
and we get X = 2.
Thus, number of girls initially = 4X = 8
Ans: C
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 21 Apr 2026
Posts: 22,276
Own Kudos:
Given Kudos: 302
Status:Founder & CEO
Affiliations: Target Test Prep
Location: United States (CA)
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 22,276
Kudos: 26,526
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
Some boys and girls are having a car wash to raise money for a class trip to China. Initially 40% of the group are girls. Shortly thereafter two girls leave and two boys arrive, and then 30% of the group are girls. How many girls were initially in the group?

(A) 4
(B) 6
(C) 8
(D) 10
(E) 12

We can let the original number of girls = 0.4n and the original number of boys = 0.6n.

Since two girls leave and two boys arrive, leaving 30% of the group as girls, we have:

(0.4n - 2)/(n - 2 + 2) = 3/10

(0.4n - 2)/n = 3/10

10(0.4n - 2) = 3n

4n - 20 = 3n

n = 20

Therefore, there were 0.4 x 20 = 8 girls originally.

Answer: C
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,954
Own Kudos:
Posts: 38,954
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
109729 posts
Tuck School Moderator
853 posts