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

It is currently 17 Feb 2020, 13:15

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

At a certain rate of simple interest, a principal becomes three times

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

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 61243
At a certain rate of simple interest, a principal becomes three times  [#permalink]

Show Tags

New post 31 Dec 2019, 01:52
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

39% (02:00) correct 61% (01:23) wrong based on 33 sessions

HideShow timer Statistics

Manager
Manager
avatar
G
Joined: 10 Dec 2017
Posts: 178
Location: India
At a certain rate of simple interest, a principal becomes three times  [#permalink]

Show Tags

New post 06 Jan 2020, 06:27
1
Bunuel wrote:
At a certain rate of simple interest, a principal becomes three times in 15 years. In how many years will the principal amount become nine times?

A. 45 years
B. 30 years
C. 60 years
D. 75 years
E. None of these


\(3=(1+X/100)^(15)\)
3=1+15X/100
X=200/15
and
\(9=(1+X/100)^q\)
\(9=1+qX/100\)
\(8=qX/100\)
\(q=800/X\)
\(q=800/(200/15)\)
q=60 years
C:)
Board of Directors
User avatar
D
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4845
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)
GMAT ToolKit User
At a certain rate of simple interest, a principal becomes three times  [#permalink]

Show Tags

New post 06 Jan 2020, 06:35
1
Bunuel wrote:
At a certain rate of simple interest, a principal becomes three times in 15 years. In how many years will the principal amount become nine times?

A. 45 years
B. 30 years
C. 60 years
D. 75 years
E. None of these


Given

\(P = 1, t = 15 , r = ? , A = 3 , i = 2\)

Find i -

\(\frac{ptr}{100} = i\)

Or, 1*15*r = 200

Or, r = 13.33 %

We need to find t now

Given \(i = 8 , p = 1 , t =? r = 13\) (say)

So, \(8 = \frac{1*t*13}{100}\)

Or, \(t\) ~ \(60\) , Answer must be (C)
_________________
Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )
Intern
Intern
User avatar
B
Joined: 30 May 2017
Posts: 43
Location: India
Concentration: Finance, Strategy
Schools: Wharton, IESE, ISB, NUS
GPA: 4
WE: Engineering (Consulting)
GMAT ToolKit User Premium Member CAT Tests
Re: At a certain rate of simple interest, a principal becomes three times  [#permalink]

Show Tags

New post 06 Jan 2020, 10:45
2
The SI is always same each year for a principal and same rate of interest.

Using this principle we can infer, if Principal becomes three times in 15 years, then Amount = 3P
However P was already invested , so Cumulative Interest in 15 years is actually I= 2P

now its a simple relation calculation

For Amount to become 9P , I = 8P

I becomes 2P in 15 years
then I becomes 8P in 15*4 = 60 Years

Answer is 60 years
_________________
You say this is a problem , I say this must be an opportunity
GMAT Club Bot
Re: At a certain rate of simple interest, a principal becomes three times   [#permalink] 06 Jan 2020, 10:45
Display posts from previous: Sort by

At a certain rate of simple interest, a principal becomes three times

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





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