GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

 It is currently 16 Jul 2020, 06:38

### 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

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

# Molly worked at an amusement park over the summer.Every two weeks she

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 65384
Molly worked at an amusement park over the summer.Every two weeks she  [#permalink]

### Show Tags

07 Apr 2020, 06:25
00:00

Difficulty:

55% (hard)

Question Stats:

53% (02:16) correct 47% (02:50) wrong based on 32 sessions

### HideShow timer Statistics

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

_________________
Intern
Joined: 14 Jan 2020
Posts: 34
GMAT 1: 760 Q51 V41
Re: Molly worked at an amusement park over the summer.Every two weeks she  [#permalink]

### Show Tags

07 Apr 2020, 07:24
Bunuel wrote:
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

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
_________________
Reach out for personalized GMAT Coaching by a 99%iler
at-
prathyusha3@gmail.com
Senior Manager
Joined: 14 Oct 2019
Posts: 406
Location: India
GPA: 4
WE: Engineering (Energy and Utilities)
Re: Molly worked at an amusement park over the summer.Every two weeks she  [#permalink]

### Show Tags

07 Apr 2020, 07:29
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

Intern
Joined: 07 Apr 2020
Posts: 44
Molly worked at an amusement park over the summer.Every two weeks she  [#permalink]

### Show Tags

07 Apr 2020, 07:43
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.

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

Intern
Joined: 22 Oct 2019
Posts: 11
Location: Russian Federation
Schools: Erasmus (S)
Re: Molly worked at an amusement park over the summer.Every two weeks she  [#permalink]

### Show Tags

08 Apr 2020, 09:39
Is there any other method except straightforward math?
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 11122
Location: United States (CA)
Re: Molly worked at an amusement park over the summer.Every two weeks she  [#permalink]

### Show Tags

15 Apr 2020, 08:29
1
Bunuel wrote:
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

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.

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com

250 REVIEWS

5-STAR RATED ONLINE GMAT QUANT SELF STUDY COURSE

NOW WITH GMAT VERBAL (BETA)

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

Intern
Joined: 14 Mar 2020
Posts: 1
Molly worked at an amusement park over the summer.Every two weeks she  [#permalink]

### Show Tags

16 Apr 2020, 14:08
ArnoldPushkin wrote:
Is there any other method except straightforward math?

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
Molly worked at an amusement park over the summer.Every two weeks she   [#permalink] 16 Apr 2020, 14:08