Last visit was: 21 May 2026, 08:49 It is currently 21 May 2026, 08:49
Home
Messages
Tests
Schools
Events
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
Back to Forum
Create Topic
User avatar
kevincan
User avatar
GMAT Instructor
Joined: 04 Jul 2006
Last visit: 21 May 2026
Posts: 1,800
Own Kudos:
2,550
 [3]
Given Kudos: 220
GRE 1: Q170 V170
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
GRE 1: Q170 V170
Posts: 1,800
Kudos: 2,550
 [3]
An HR manager reviewed the first third of a stack of resumes 29 Mar 2026, 03:46
Kudos
Add Kudos
3
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

15% (low)

Question Stats:

86% (02:23) correct 14% (02:18) wrong based on 57 sessions

History

Date
Time
Result
Not Attempted Yet
An HR manager reviewed the first third of a stack of resumes at a rate of 9 resumes per hour, the second third at a rate of 18 resumes per hour, and the final third at a rate of 36 resumes per hour. If it took the manager 7 hours to review all of the resumes, how many resumes were in the stack?

A) 54
B) 72
C) 90
D) 108
E) 126
ShowHide Answer
Official Answer
D
User avatar
AbdiAR
User avatar
Joined: 11 Jan 2024
Last visit: 21 May 2026
Posts: 2
Given Kudos: 8
Posts: 2
Kudos: 0
An HR manager reviewed the first third of a stack of resumes 29 Mar 2026, 04:29
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Let x = the number of resumes

_____ R ____ T ______ W
1st _ 9 ___________ x/3
2nd _ 18 ___________ x/3
3rd _ 36 ___________ x/3

T1+T2+T3 = Time total
T1: x/3÷9 = x/27
T2: x/3÷18 = x/54
T3: x/3÷36 = x/108

x/27+x/54+x/108 = 7

Multiplying everything by the LCM

4x+2x+x = 756
7x= 756
x = 108

Answer: D
User avatar
poojaarora1818
User avatar
Joined: 30 Jul 2019
Last visit: 21 May 2026
Posts: 1,634
Own Kudos:
788
 [2]
Given Kudos: 3,856
Location: India
Concentration: General Management, Economics
Schools: Duke '27 Haas '27 Kelley '27 Kellogg '27 McDonough '27
GPA: 3
WE:Human Resources (Real Estate)
Products:
GMAT Club Tests
Schools: Duke '27 Haas '27 Kelley '27 Kellogg '27 McDonough '27
Posts: 1,634
Kudos: 788
 [2]
An HR manager reviewed the first third of a stack of resumes 29 Mar 2026, 04:57
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Let's apply the matrix approach

RateTime Work
First Third9r/hN/9N
Second Third18r/hN/18N
Final Third36r/hN/36N

We know the total time took by manager to review all the resumes are 7 hours.

N/9 + N/18 + N/36 = 7

By solving the above equation we get

N = 36

Total number of resumes = 3N = 108

Answer: D


kevincan
An HR manager reviewed the first third of a stack of resumes at a rate of 9 resumes per hour, the second third at a rate of 18 resumes per hour, and the final third at a rate of 36 resumes per hour. If it took the manager 7 hours to review all of the resumes, how many resumes were in the stack?

A) 54
B) 72
C) 90
D) 108
E) 126
Show more
User avatar
Edskore
User avatar
Joined: 29 Dec 2022
Last visit: 20 May 2026
Posts: 306
Own Kudos:
140
Given Kudos: 5
Posts: 306
Kudos: 140
An HR manager reviewed the first third of a stack of resumes 29 Mar 2026, 06:22
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Classic Work and Rate setup. The variable definition is the part that bites most people.

Let the total number of resumes = N. Each third of the stack has N/3 resumes.

1. Time to review the first third: (N/3) / 9 = N/27 hours
2. Time to review the second third: (N/3) / 18 = N/54 hours
3. Time to review the final third: (N/3) / 36 = N/108 hours

Total time = N/27 + N/54 + N/108 = 7

Finding the LCM of 27, 54, 108 — it's 108.

So: 4N/108 + 2N/108 + N/108 = 7
7N/108 = 7
N = 108

Answer is D.

The common trap is setting N equal to one-third of the stack instead of the whole thing, which leads to 36 and then having to remember to multiply back. Defining N as the total from the start avoids that confusion. Also, a lot of people try to work with the rates directly (9+18+36 and some average) which doesn't work for unequal distances — you can only average rates when equal times are spent, not equal amounts of work.
User avatar
Dereno
User avatar
Joined: 22 May 2020
Last visit: 21 May 2026
Posts: 1,399
Own Kudos:
1,381
 [1]
Given Kudos: 431
Products:
GMAT Club Tests Forum Quiz
Posts: 1,399
Kudos: 1,381
 [1]
An HR manager reviewed the first third of a stack of resumes 29 Mar 2026, 07:24
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
kevincan
An HR manager reviewed the first third of a stack of resumes at a rate of 9 resumes per hour, the second third at a rate of 18 resumes per hour, and the final third at a rate of 36 resumes per hour. If it took the manager 7 hours to review all of the resumes, how many resumes were in the stack?

A) 54
B) 72
C) 90
D) 108
E) 126
Show more
Let the total resumes be 3x.

x resumes at the rate of 9 resumes per hour, 18 resumes per hour, and 36 resumes per hour.

If we assume the total work to be LCM (9,18,36) = 36 units = x.

Efficiency at the respective stacks are 4,2,1 respectively.

Total hours = 4+2+1 = 7 hours.

Total resumes = 3x = 3*36 = 108.

Option D
Moderators:
Bunuel
Math Expert
110764 posts
Krunaal
Tuck School Moderator
852 posts