Last visit was: 23 Apr 2026, 12:40 It is currently 23 Apr 2026, 12:40
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
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,785
Own Kudos:
810,847
 [11]
Given Kudos: 105,853
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,785
Kudos: 810,847
 [11]
Sofia runs a business delivering boxes of frequently used household su 18 Mar 2020, 07:55
Kudos
Add Kudos
11
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

35% (medium)

Question Stats:

71% (01:51) correct 29% (01:45) wrong based on 306 sessions

History

Date
Time
Result
Not Attempted Yet
Sofia runs a business delivering boxes of frequently used household supplies to monthly subscribers. After hiring a workflow manager, she delivered 20 percent more boxes per month while working 20 percent fewer hours herself each month. Hiring a workflow manager increased Sofia’s personal productivity per hour by what percent?

A. 40%
B. 50%
C. 60%
D. 140%
E. 150%
ShowHide Answer
Official Answer
B
User avatar
Mansoor50
User avatar
Joined: 29 May 2017
Last visit: 04 Jul 2021
Posts: 139
Own Kudos:
31
Given Kudos: 63
Location: Pakistan
Concentration: Social Entrepreneurship, Sustainability
Posts: 139
Kudos: 31
Sofia runs a business delivering boxes of frequently used household su 27 Mar 2020, 04:53
Kudos
Add Kudos
Bookmarks
Bookmark this Post
assume she worked 40 hrs/week thus 160 hours/month

she was delvering 100/160 per hour
after workflow
she was delivering 120/128 , 128 is 80% of 160

the difference is: 120/128 - 100/160 which is 5/16 improvement


just a shot in the dark!
User avatar
CrackverbalGMAT
User avatar
Major Poster
Joined: 03 Oct 2013
Last visit: 22 Apr 2026
Posts: 4,846
Own Kudos:
9,181
 [2]
Given Kudos: 226
Affiliations: CrackVerbal
Location: India
Expert
Expert reply
Posts: 4,846
Kudos: 9,181
 [2]
Sofia runs a business delivering boxes of frequently used household su 27 Mar 2020, 05:01
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Assuming simple values is probably the fastest and the best method in solving this question.

Let’s assume that Sofia used to deliver 100 boxes a month before the workflow manager was hired. Let’s also say that she worked a total of 10 hours to do this work. Her productivity would then be 10 boxes per hour.

Once the workflow manager was hired, Sofia delivered 20 percent more boxes. This means that she’s now able to deliver 120 boxes. At the same time, she worked 20 percent fewer hours to get this work done which means she worked a total of 8 hours. Her productivity would now be 15 boxes per hour (120 boxes/8 hours).

From 10 boxes/hour to 15 boxes/hour, we see that the increase in Sofia's productivity is 50%. The correct answer option is B.

Hope that helps!
User avatar
Mansoor50
User avatar
Joined: 29 May 2017
Last visit: 04 Jul 2021
Posts: 139
Own Kudos:
31
Given Kudos: 63
Location: Pakistan
Concentration: Social Entrepreneurship, Sustainability
Posts: 139
Kudos: 31
Sofia runs a business delivering boxes of frequently used household su 27 Mar 2020, 05:06
Kudos
Add Kudos
Bookmarks
Bookmark this Post
ArvindCrackVerbal
Assuming simple values is probably the fastest and the best method in solving this question.

Let’s assume that Sofia used to deliver 100 boxes a month before the workflow manager was hired. Let’s also say that she worked a total of 10 hours to do this work. Her productivity would then be 10 boxes per hour.

Once the workflow manager was hired, Sofia delivered 20 percent more boxes. This means that she’s now able to deliver 120 boxes. At the same time, she worked 20 percent fewer hours to get this work done which means she worked a total of 8 hours. Her productivity would now be 15 boxes per hour (120 boxes/8 hours).

From 10 boxes/hour to 15 boxes/hour, we see that the increase in Sofia's productivity is 50%. The correct answer option is B.

Hope that helps!
Show more

hi...i chose 40 hr per week...and didnt get the answer....can you look at my solution and tell me where i went wrong?
User avatar
CrackverbalGMAT
User avatar
Major Poster
Joined: 03 Oct 2013
Last visit: 22 Apr 2026
Posts: 4,846
Own Kudos:
9,181
 [1]
Given Kudos: 226
Affiliations: CrackVerbal
Location: India
Expert
Expert reply
Posts: 4,846
Kudos: 9,181
 [1]
Sofia runs a business delivering boxes of frequently used household su 27 Mar 2020, 06:40
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Mansoor50
ArvindCrackVerbal
Assuming simple values is probably the fastest and the best method in solving this question.

Let’s assume that Sofia used to deliver 100 boxes a month before the workflow manager was hired. Let’s also say that she worked a total of 10 hours to do this work. Her productivity would then be 10 boxes per hour.

Once the workflow manager was hired, Sofia delivered 20 percent more boxes. This means that she’s now able to deliver 120 boxes. At the same time, she worked 20 percent fewer hours to get this work done which means she worked a total of 8 hours. Her productivity would now be 15 boxes per hour (120 boxes/8 hours).

From 10 boxes/hour to 15 boxes/hour, we see that the increase in Sofia's productivity is 50%. The correct answer option is B.

Hope that helps!

hi...i chose 40 hr per week...and didnt get the answer....can you look at my solution and tell me where i went wrong?
Show more


Hello Mansoor,

You have brought in too many values while trying to solve the question. The problem with this is that more variables means more things to keep a tab on. When you have to handle more variables under a time constraint, it's very natural to miss some of them out.

That's exactly what has happened here. You have just found the difference between the two different cases of productivity. But, you have forgotten to compare it with the initial value and that is where the slip up has happened.

Remember, Percentage Increase = \(\frac{Final Value - Initial Value }{ Initial Value}\) * 100.

You did find out the numerator, but forgot to compare it with the denominator and simplify. Also, you did not simplify 100/160 to 5/8 and 120/128 to 15/16; instead you kept using the same values to find the difference. Under a time constraint, when you feed your brain with bigger numbers, many times it gets overwhelmed and that's when the calculation mistakes crop up. So, remember to simplify fractions to their lowest form as much as you can.

So, here's what you SHOULD HAVE done:

Percentage Increase = (15/16) - (5/8) / (5/8) * 100 = (5/16) / (5/8) * 100 = 1/2 * 100 = 50%.

You faltered at the final step, hard luck! But hey, it was just a minor detail that you overlooked, so it's okay. Your reasoning wasn't faulty.

Hope that helps!
User avatar
Mansoor50
User avatar
Joined: 29 May 2017
Last visit: 04 Jul 2021
Posts: 139
Own Kudos:
31
Given Kudos: 63
Location: Pakistan
Concentration: Social Entrepreneurship, Sustainability
Posts: 139
Kudos: 31
Sofia runs a business delivering boxes of frequently used household su 28 Mar 2020, 01:22
Kudos
Add Kudos
Bookmarks
Bookmark this Post
ArvindCrackVerbal
Mansoor50
ArvindCrackVerbal
Assuming simple values is probably the fastest and the best method in solving this question.

Let’s assume that Sofia used to deliver 100 boxes a month before the workflow manager was hired. Let’s also say that she worked a total of 10 hours to do this work. Her productivity would then be 10 boxes per hour.

Once the workflow manager was hired, Sofia delivered 20 percent more boxes. This means that she’s now able to deliver 120 boxes. At the same time, she worked 20 percent fewer hours to get this work done which means she worked a total of 8 hours. Her productivity would now be 15 boxes per hour (120 boxes/8 hours).

From 10 boxes/hour to 15 boxes/hour, we see that the increase in Sofia's productivity is 50%. The correct answer option is B.

Hope that helps!

hi...i chose 40 hr per week...and didnt get the answer....can you look at my solution and tell me where i went wrong?


Hello Mansoor,

You have brought in too many values while trying to solve the question. The problem with this is that more variables means more things to keep a tab on. When you have to handle more variables under a time constraint, it's very natural to miss some of them out.

That's exactly what has happened here. You have just found the difference between the two different cases of productivity. But, you have forgotten to compare it with the initial value and that is where the slip up has happened.

Remember, Percentage Increase = \(\frac{Final Value - Initial Value }{ Initial Value}\) * 100.

You did find out the numerator, but forgot to compare it with the denominator and simplify. Also, you did not simplify 100/160 to 5/8 and 120/128 to 15/16; instead you kept using the same values to find the difference. Under a time constraint, when you feed your brain with bigger numbers, many times it gets overwhelmed and that's when the calculation mistakes crop up. So, remember to simplify fractions to their lowest form as much as you can.

So, here's what you SHOULD HAVE done:

Percentage Increase = (15/16) - (5/8) / (5/8) * 100 = (5/16) / (5/8) * 100 = 1/2 * 100 = 50%.

You faltered at the final step, hard luck! But hey, it was just a minor detail that you overlooked, so it's okay. Your reasoning wasn't faulty.

Hope that helps!
Show more

a big thank you!!
its good to know my thought process was correct...means a lot
avatar
rohitgupta2362
avatar
Joined: 02 Dec 2017
Last visit: 11 Apr 2020
Posts: 6
Own Kudos:
2
 [2]
Given Kudos: 3
Posts: 6
Kudos: 2
 [2]
Sofia runs a business delivering boxes of frequently used household su 28 Mar 2020, 12:03
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
The way I approached this questions is mentioned below:
Productivity = Total number of boxes delivered per unit time.
so, P1 = n/x
P2 = 1.2n/0.8x
Increase in Productivity = (P2-P1)/P1 = 50%
User avatar
NightWalker
User avatar
Joined: 24 Nov 2019
Last visit: 09 Jun 2023
Posts: 144
Own Kudos:
51
Given Kudos: 132
Concentration: Strategy, International Business
Schools: Kenan-Flagler '24 (WL) Darden '25 (A)
GMAT 1: 760 Q51 V41 (Online)
Schools: Kenan-Flagler '24 (WL) Darden '25 (A)
GMAT 1: 760 Q51 V41 (Online)
Posts: 144
Kudos: 51
Sofia runs a business delivering boxes of frequently used household su 06 Aug 2021, 08:49
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Assumptions:

earlier: 100 boxes in 100 hours. Productivity =1
Now : 120 boxes in 80 hours. Productivity = 1.5
Change in productivity = 1.5-1 = 0.5
% change = (0.5/1) * 100 = 50%
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,964
Own Kudos:
1,117
Posts: 38,964
Kudos: 1,117
Sofia runs a business delivering boxes of frequently used household su 28 Mar 2023, 02:24
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:
Bunuel
Math Expert
109785 posts
Krunaal
Tuck School Moderator
853 posts