GMAT Changed on April 16th - Read about the latest changes here

It is currently 27 May 2018, 18:16

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Mani saves money in a jar at home for six months. The first month he

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 45498
Mani saves money in a jar at home for six months. The first month he [#permalink]

Show Tags

New post 25 Apr 2018, 21:51
Expert's post
2
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

83% (02:06) correct 17% (02:42) wrong based on 30 sessions

HideShow timer Statistics

Mani saves money in a jar at home for six months. The first month he saves S dollars. Each month thereafter, Mani saves 1/2 of what he has saved the previous month. If Mani’s total savings at the end of the six months is $393.75, how much money does he save the sixth month?

(A) $6.25
(B) $7.50
(C) $12.50
(D) $18.75
(E) $25.00

_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Manager
Manager
User avatar
S
Joined: 28 Nov 2017
Posts: 99
Location: Uzbekistan
Premium Member
Re: Mani saves money in a jar at home for six months. The first month he [#permalink]

Show Tags

New post 25 Apr 2018, 22:34
Bunuel wrote:
Mani saves money in a jar at home for six months. The first month he saves S dollars. Each month thereafter, Mani saves 1/2 of what he has saved the previous month. If Mani’s total savings at the end of the six months is $393.75, how much money does he save the sixth month?

(A) $6.25
(B) $7.50
(C) $12.50
(D) $18.75
(E) $25.00


\(S+\frac{1}{2}S+\frac{1}{4}S+\frac{1}{8}S+\frac{1}{16}S+\frac{1}{32}S=393\frac{3}{4}\)

\(\frac{63}{32}S=\frac{1575}{4}\)

Note that \(1575*4=6300\).

So, \(S=200\).

We are asked to find the amount of money he saved the sixth month. That is \(\frac{200}{32}=6.25\)

Answer: A
_________________

Kindest Regards!
Tulkin.

Manager
Manager
avatar
B
Joined: 24 Jun 2013
Posts: 63
GMAT ToolKit User
Re: Mani saves money in a jar at home for six months. The first month he [#permalink]

Show Tags

New post 25 Apr 2018, 22:42
Bunuel wrote:
Mani saves money in a jar at home for six months. The first month he saves S dollars. Each month thereafter, Mani saves 1/2 of what he has saved the previous month. If Mani’s total savings at the end of the six months is $393.75, how much money does he save the sixth month?

(A) $6.25
(B) $7.50
(C) $12.50
(D) $18.75
(E) $25.00


he saves S in first month thereafter 1/2 of what he saved the previous month. so for six months

S+\(\frac{1}{2}\)S+\(\frac{1}{4}\)S+\(\frac{1}{8}\)S+\(\frac{1}{16}\)S+\(\frac{1}{32}\)S = 393.75

simplify we get , \(\frac{63}{32}\)S= 393.75

we are asked to find \(\frac{1}{32}\)S (Sixth month saving)

So \(\frac{S}{32}\)=\(\frac{393.75*32}{63*32}\)S= 6.25
_________________

If this post helped you learn something pls give kudos

Senior Manager
Senior Manager
avatar
S
Joined: 02 Oct 2017
Posts: 499
Re: Mani saves money in a jar at home for six months. The first month he [#permalink]

Show Tags

New post 13 May 2018, 10:14
Above question can be solved by two methods

I) S+ S/2 + S/4 +S/8+ S/16+ S/32= 393.75

Calculate S and then S/32 for last value

II) by calculating sum of gp with r=1/2

S((1/2)^6-1)/ (1/2-1)=393.75

63S/32=393.75

S=6.25*32

Last term =S*(1/2)^6=6.25

Give kudos if it helps to encourage me posting

Posted from my mobile device
BSchool Forum Moderator
User avatar
V
Joined: 26 Feb 2016
Posts: 2587
Location: India
GPA: 3.12
Premium Member CAT Tests
Re: Mani saves money in a jar at home for six months. The first month he [#permalink]

Show Tags

New post 13 May 2018, 12:44
Bunuel wrote:
Mani saves money in a jar at home for six months. The first month he saves S dollars. Each month thereafter, Mani saves 1/2 of what he has saved the previous month. If Mani’s total savings at the end of the six months is $393.75, how much money does he save the sixth month?

(A) $6.25
(B) $7.50
(C) $12.50
(D) $18.75
(E) $25.00



Since Mani's total savings at the end of six months is $393.75 and he was able
to save half of what he had saved the previous month, it is also safe to assume
that the savings double each month(if we begin calculating from the last month)

Let's consider Option A(6.25) as the amount he would have saved in the 6th month.
So, the 5th month he would have saved xx.50 and every month after that he would
have saved xx.00. The sum would be xxx.75 and could be our answer.

Let's consider Option D(18.75). So in the 5th month, he would save xx.50 and there
after every month he would save xx.00. The sum would be xxx.25. We can eliminate
Option B,C, and E for similar reasons

Therefore, Option A($6.25) is the amount Mani saves in the sixth month.
_________________

You've got what it takes, but it will take everything you've got

Re: Mani saves money in a jar at home for six months. The first month he   [#permalink] 13 May 2018, 12:44
Display posts from previous: Sort by

Mani saves money in a jar at home for six months. The first month he

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.