Last visit was: 24 Apr 2026, 09:47 It is currently 24 Apr 2026, 09:47
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: 24 Apr 2026
Posts: 109,814
Own Kudos:
Given Kudos: 105,871
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,814
Kudos: 811,030
 [24]
1
Kudos
Add Kudos
23
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 24 Apr 2026
Posts: 109,814
Own Kudos:
811,030
 [4]
Given Kudos: 105,871
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,814
Kudos: 811,030
 [4]
1
Kudos
Add Kudos
3
Bookmarks
Bookmark this Post
General Discussion
User avatar
sj296
Joined: 09 Jul 2014
Last visit: 19 Mar 2025
Posts: 305
Own Kudos:
397
 [2]
Given Kudos: 346
Location: India
Concentration: General Management, Finance
Schools: ISB '24
Schools: ISB '24
Posts: 305
Kudos: 397
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
pooh.2304
Joined: 11 May 2023
Last visit: 13 Dec 2024
Posts: 28
Own Kudos:
40
 [2]
Given Kudos: 25
Location: India
Concentration: Leadership, International Business
Posts: 28
Kudos: 40
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Present rate = 1/(2/3) = 3/2

Time taken to type 3/4 doc = 3/2 * 3/4 = 1/2

Remaining work = 1 - 3/4 = 1/4
Remaining time = 1 - 1/2 = 1/2
Remaining work Rate = 1/2

% decrease = (3/2 - 1/2)/(3/2) * 100 = 66 2/3% (C)
User avatar
missionmba2025
Joined: 07 May 2023
Last visit: 07 Sep 2025
Posts: 341
Own Kudos:
431
 [2]
Given Kudos: 52
Location: India
Posts: 341
Kudos: 431
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
12 Days of Christmas 🎅 GMAT Competition with Lots of Questions & Fun

After completing typing 3/4 of a document, Lana recognizes that at her present speed, she'll finish the entire document in just 2/3 of the allocated time. By what percentage should she decrease her typing speed to ensure she finishes precisely when intended?

A. \(33 \frac{1}{3}\%\)

B. \(50\%\)

C. \(66 \frac{2}{3}\%\)

D. \(75\%\)

D. \(80\%\)


 


This question was provided by GMAT Club
for the 12 Days of Christmas Competition

Win $40,000 in prizes: Courses, Tests & more

 


Assume Lana had to type in 1200 pages in 3 hours. She should have typed in 1200/3 = 400 pages per hour.

But she typed 1200 / 2 = 600 pages instead.

After completing 3/4 of 1200 i.e. 900 pages she wants to reduce her speed.

Time to complete 900 pages at her speed = 900 / 600 = 1.5 hours

So she needs to complete 300 pages in 1.5 hours, i.e. 200 pages per hour

200 = 600*x/100

x = 33.33%

Hence, she must reduce her speed by 66.66%

IMO C
avatar
DG1989
Joined: 16 Feb 2023
Last visit: 24 Dec 2024
Posts: 140
Own Kudos:
311
 [1]
Given Kudos: 9
Location: India
Concentration: Finance, Technology
Schools: Kellogg '26
GPA: 4
Schools: Kellogg '26
Posts: 140
Kudos: 311
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
After completing typing 3/4 of a document, Lana recognizes that at her present speed, she'll finish the entire document in just 2/3 of the allocated time. By what percentage should she decrease her typing speed to ensure she finishes precisely when intended?

A. 33\(\frac{1}{2}\)%
B. 50%
C. 66\(\frac{2}{3}\)%
D. 75%
E. 80%

Solution: Let original speed be x and original intended time of completion of the document be T
complete document = x * T
say 100 = x * T

Lana realizes that at current speed say y, work will be completed in \(\frac{2}{3}\)T
i.e. 100 = y * \(\frac{2}{3}\)T
this gives y = \(\frac{3}{2}\)x
or y = 1.5x

Time taken to complete \(\frac{3}{4}\) of the document say T'
75 = 1.5x * T'
or T' = 50/x

For remaining \(\frac{1}{4}\) of the document, the speed needs to be reduced from say y to y' and the time taken should be = T - T'
i.e. 25 = y' * (T - T')
25 = y' * (\(\frac{100}{x}\) - \(\frac{50}{x}\))
25 = y' * \(\frac{50}{x}\)

Thus y' = \(\frac{x}{2}\)
or y' = 0.5x

Now, Percentage reduction in the speeds required to finish the work in original intended time
= \(\frac{(y - y')}{y}\) * 100

= \(\frac{(1.5x - 0.5x)}{1.5x}\) * 100

= \(\frac{x}{1.5x}\) * 100

= \(\frac{2}{3}\) * 100
Percentage reduction = 66\(\frac{2}{3}\)%

Option C is the right answer
User avatar
Lalykys
Joined: 23 Jun 2015
Last visit: 17 Apr 2025
Posts: 37
Own Kudos:
63
 [1]
Given Kudos: 46
Posts: 37
Kudos: 63
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
After completing typing 3/4 of a document, Lana recognizes that at her present speed, she'll finish the entire document in just 2/3 of the allocated time. By what percentage should she decrease her typing speed to ensure she finishes precisely when intended?

Let's there be :
- w: the work of typing an entire document
- Phase 1 where work done is (3/4)*w and T1 the time it takes
- Phase 2 where work to be done is (1/4)*w and T2 the time it will take if Lana keeps the same speed
- T: the time allocated for the entire document
we know that T1+T2 = 2T/3
furthermore as the rate for those 2 phases is the same => 3/4T1 = 1/4T2 => T1=3T2 so 4T2=2T/3 => T2=T/6 and T1=T/2.

so after phase 1, Lana should decrease her speed so that she spend T/2 time to finish w/4:
So her new speed will be R=1/4*2/T=1/2T
knowinf that initial rate was 3/4T1=3/4*2/T=3/2T it means that Lana should decrease her speed by 3/2T-1/2T=1/T =>which represent a (1/T)/(3/2T)=> (1/T)*(2T/3) => 66-2/3%

So answer C
User avatar
ChiranjeevSingh
Joined: 22 Oct 2012
Last visit: 24 Apr 2026
Posts: 427
Own Kudos:
Given Kudos: 161
Status:Private GMAT Tutor
Location: India
Concentration: Economics, Finance
Schools: IIMA  (A)
GMAT Focus 1: 735 Q90 V85 DI85
GMAT Focus 2: 735 Q90 V85 DI85
GMAT Focus 3: 735 Q88 V87 DI84
GMAT 1: 780 Q51 V47
GRE 1: Q170 V168
Expert
Expert reply
Schools: IIMA  (A)
GMAT Focus 3: 735 Q88 V87 DI84
GMAT 1: 780 Q51 V47
GRE 1: Q170 V168
Posts: 427
Kudos: 3,209
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Here's how I solved it.

At her current speed, Lana would finish the entire document in two-thirds of the allocated time. She has already completed three-fourths of the document.
This means she has used (3/4) × (2/3) = 1/2 of the allocated time to complete three-fourths of the document.

Now, she has the remaining half of the time left, and she needs to complete the remaining one-fourth of the document.
In the first half of the time, she completed three-fourths of the document. In the next half, she needs to complete only one-fourth.

Attachment:
cj_1.png
cj_1.png [ 1.03 MiB | Viewed 1804 times ]

This means her typing speed must reduce to one-third of her original speed (because earlier she was doing 3 parts in the same time, now only 1 part).
Thus, her speed must decrease by two-thirds.

A decrease of two-thirds corresponds to 66 2/3%.
Therefore, the answer is 66 2/3%.
Moderators:
Math Expert
109814 posts
Tuck School Moderator
853 posts