Last visit was: 25 Apr 2026, 20:15 It is currently 25 Apr 2026, 20:15
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: 25 Apr 2026
Posts: 109,830
Own Kudos:
811,288
 [6]
Given Kudos: 105,886
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: 109,830
Kudos: 811,288
 [6]
Molly worked at an amusement park over the summer.Every two weeks she 07 Apr 2020, 07:25
Kudos
Add Kudos
6
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:

85% (hard)

Question Stats:

60% (02:50) correct 40% (02:47) wrong based on 163 sessions

History

Date
Time
Result
Not Attempted Yet
Molly worked at an amusement park over the summer.Every two weeks she was paid according to the following schedule:at the end of the first two weeks she received $160.At the end of each subsequent two week period she received $1, plus an additional amount equal to the sum of all the payments she had received in the previous weeks.How much money was Molly paid during full 10 weeks of summer?

A. 644
B. 1288
C. 1770
D. 2575
E. 3229
ShowHide Answer
Official Answer
D
User avatar
prathyushaR
User avatar
Joined: 14 Jan 2020
Last visit: 07 Jan 2021
Posts: 25
Own Kudos:
52
 [1]
Given Kudos: 27
GMAT 1: 760 Q51 V41
GMAT 1: 760 Q51 V41
Posts: 25
Kudos: 52
 [1]
Molly worked at an amusement park over the summer.Every two weeks she 07 Apr 2020, 08:24
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Bunuel
Molly worked at an amusement park over the summer.Every two weeks she was paid according to the following schedule:at the end of the first two weeks she received $160.At the end of each subsequent two week period she received $1, plus an additional amount equal to the sum of all the payments she had received in the previous weeks.How much money was Molly paid during full 10 weeks of summer?

A. 644
B. 1288
C. 1770
D. 2575
E. 3229
Show more
after 2 weeks : 160$
after 4 weeks :1+160$=161$
after 6weeks : 1+161+160$=322$
after 8 weeks :1+322+161+160$=644$
after 10 weeks :1+644+322+161+160$=1288$
total sum= 1288+644+322+161+160=2575$
OPTION D
User avatar
preetamsaha
User avatar
Joined: 14 Oct 2019
Last visit: 18 Jan 2025
Posts: 337
Own Kudos:
563
Given Kudos: 127
Status:Today a Reader; Tomorrow a Leader.
Location: India
GPA: 4
WE:Engineering (Energy)
Posts: 337
Kudos: 563
Molly worked at an amusement park over the summer.Every two weeks she 07 Apr 2020, 08:29
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Payment after 2 weeks: $160

Payment after 4 weeks: 1 + $160 = $161

Payment after 6 weeks: 1 + $160 + $161 = $322

Payment after 8 weeks: 1 + $160 + $161 + $322 = $644

Payment after 10 weeks: 1 + $160 + $161 + $322 + 644 = $1288

So, TOTAL of all payments = $160 + $161 + $322 + $644 + $1288

so,money was Molly paid during full 10 weeks of summer = $2575

correct answer D
User avatar
Enchanting
User avatar
Joined: 07 Apr 2020
Last visit: 16 Jan 2022
Posts: 42
Own Kudos:
100
 [1]
Given Kudos: 2
Posts: 42
Kudos: 100
 [1]
Molly worked at an amusement park over the summer.Every two weeks she 07 Apr 2020, 08:43
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Solution:

    • \(Money \ she \ received \ after \ every \ 2 \ weeks = sum \ of \ money \ received \ last \ weeks + 1\)

    • Total money paid = money for first two week + money for third and fourth week + money for fifth and sixth week + money for seventh and eight week + money for night and tenth week.

    • \(Total \ money \ paid = 160 + (160+1) + (160+161+1) + (160 + 161 +322+1 ) + (160 + 161 + 322 + 644+1) = $ 2575\)

Answer : Option D
User avatar
ArnoldPushkin
User avatar
Joined: 22 Oct 2019
Last visit: 17 Apr 2022
Posts: 10
Own Kudos:
10
Given Kudos: 57
Location: Russian Federation
Posts: 10
Kudos: 10
Molly worked at an amusement park over the summer.Every two weeks she 08 Apr 2020, 10:39
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Is there any other method except straightforward math?
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 25 Apr 2026
Posts: 22,286
Own Kudos:
26,537
 [1]
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: 22,286
Kudos: 26,537
 [1]
Molly worked at an amusement park over the summer.Every two weeks she 15 Apr 2020, 09:29
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
Molly worked at an amusement park over the summer.Every two weeks she was paid according to the following schedule:at the end of the first two weeks she received $160.At the end of each subsequent two week period she received $1, plus an additional amount equal to the sum of all the payments she had received in the previous weeks.How much money was Molly paid during full 10 weeks of summer?

A. 644
B. 1288
C. 1770
D. 2575
E. 3229
Show more

After weeks 1 and 2, she earned 160 dollars.

After weeks 3 and 4, she earned 1 + 160 = 161 dollars.

After weeks 5 and 6, she earned 1 + 160 + 161 = 322 dollars.

After weeks 7 and 8, she earned 1 + 160 + 161 + 322 = 644 dollars.

After weeks 9 and 10, she earned 1 + 160 + 161 + 322 + 644 = 1288 dollars.

Thus, the total she earned in 10 weeks is 160 + 161 + 322 + 644 + 1288 = 2575 dollars.

Answer: D
avatar
georgos8888
avatar
Joined: 14 Mar 2020
Last visit: 30 Jun 2022
Posts: 1
Own Kudos:
3
 [3]
Given Kudos: 42
Posts: 1
Kudos: 3
 [3]
Molly worked at an amusement park over the summer.Every two weeks she 16 Apr 2020, 15:08
2
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
ArnoldPushkin
Is there any other method except straightforward math?
Show more

Yes since every answer ends in a different unit digit you can try and find the unit digit of the sum with out adding all the numbers.

you can write the amount she earns each month as

1)160
2)1+160
3)1+1+160+160
4)1+1+1+1+160+160 +160+160
5)1+1+1+1+1+1+1+1+160+160 +160+160 +160+160+160+160

Now you count all the ones

The sum of ones= 15

The only answer that ends in 5 is D

I think thats the fastest way to solve this question under 2 min. If anyone figure out an even faster way please make sure to share it :)
User avatar
SharukhB
User avatar
Joined: 03 Jul 2025
Last visit: 25 Apr 2026
Posts: 12
Own Kudos:
21
Given Kudos: 13
Posts: 12
Kudos: 21
Molly worked at an amusement park over the summer.Every two weeks she 15 Oct 2025, 03:56
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I did something similar:

Let 160 be x

Therefore after 2 weeks x
After 4 weeks 2x+1
After 6 weeks 3x+2
After 8 weeks 4x+3
After 10 weeks 5x+4

Total = x+2x+3x+4x+5x+ 15 (only answer with 15 is D)

Total = 16x+15, now substitute x =160 = 16*16 =256 i.e. 2560 +15 = 2575

georgos8888


Yes since every answer ends in a different unit digit you can try and find the unit digit of the sum with out adding all the numbers.

you can write the amount she earns each month as

1)160
2)1+160
3)1+1+160+160
4)1+1+1+1+160+160 +160+160
5)1+1+1+1+1+1+1+1+160+160 +160+160 +160+160+160+160

Now you count all the ones

The sum of ones= 15

The only answer that ends in 5 is D

I think thats the fastest way to solve this question under 2 min. If anyone figure out an even faster way please make sure to share it :)
Show more
Moderators:
Bunuel
Math Expert
109830 posts
Krunaal
Tuck School Moderator
852 posts