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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 350,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

A bank offers an interest of 5% per annum compounded annua [#permalink]
11 Jun 2013, 02:58

2

This post received KUDOS

2

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

25% (medium)

Question Stats:

74% (02:31) correct
26% (01:36) wrong based on 141 sessions

A bank offers an interest of 5% per annum compounded annually on all its deposits. If $10,000 is deposited, what will be the ratio of the interest earned in the 4th year to the interest earned in the 5th year?

A. 1:5 B. 625:3125 C. 100:105 D. 100^4:105^4 E. 725:3225

Re: A bank offers an interest of 5% per annum compounded annua [#permalink]
11 Jun 2013, 04:59

9

This post received KUDOS

Expert's post

2

This post was BOOKMARKED

emmak wrote:

A bank offers an interest of 5% per annum compounded annually on all its deposits. If $10,000 is deposited, what will be the ratio of the interest earned in the 4th year to the interest earned in the 5th year?

A. 1:5 B. 625:3125 C. 100:105 D. 1004:1054 E. 725:3225

The interest earned in the 1st year = $500 The interest earned in the 2nd year = $500*1.05 The interest earned in the 3rd year = $500*1.05^2 The interest earned in the 4th year = $500*1.05^3 The interest earned in the 5th year = $500*1.05^4

Re: A bank offers an interest of 5% per annum compounded annua [#permalink]
14 Jun 2013, 02:22

emmak wrote:

A bank offers an interest of 5% per annum compounded annually on all its deposits. If $10,000 is deposited, what will be the ratio of the interest earned in the 4th year to the interest earned in the 5th year?

A. 1:5 B. 625:3125 C. 100:105 D. 1004:1054 E. 725:3225

Hi Bunuel, Here is my approach: is this correct?

Interest earned in 4 year= 10000(1+0.05)^4

Interest earned in 5 year= 10000(1+0.05)^5

Ratio= {10000(1.05)^4}/{10000(1.05^5)} =>1.05^4/1.05^5 =>1/1.05 Multiplied by 100 in both numerator and denominator gives 100:105

Hence Ans:C _________________

Do not forget to hit the Kudos button on your left if you find my post helpful.

Re: A bank offers an interest of 5% per annum compounded annua [#permalink]
14 Jun 2013, 02:28

Expert's post

atalpanditgmat wrote:

emmak wrote:

A bank offers an interest of 5% per annum compounded annually on all its deposits. If $10,000 is deposited, what will be the ratio of the interest earned in the 4th year to the interest earned in the 5th year?

A. 1:5 B. 625:3125 C. 100:105 D. 1004:1054 E. 725:3225

Hi Bunuel, Here is my approach: is this correct?

Interest earned in 4 year= 10000(1+0.05)^4

Interest earned in 5 year= 10000(1+0.05)^5

Ratio= {10000(1.05)^4}/{10000(1.05^5)} =>1.05^4/1.05^5 =>1/1.05 Multiplied by 100 in both numerator and denominator gives 100:105

Re: A bank offers an interest of 5% per annum compounded annua [#permalink]
26 Oct 2013, 01:14

emmak wrote:

A bank offers an interest of 5% per annum compounded annually on all its deposits. If $10,000 is deposited, what will be the ratio of the interest earned in the 4th year to the interest earned in the 5th year?

A. 1:5 B. 625:3125 C. 100:105 D. 1004:1054 E. 725:3225

Thirty seconds approach, regardless of what the figure is at the 4th year it will at act as a base figure (100) for the next years 5% increase (to 105). So the ratio is 100:105 or option C

Re: A bank offers an interest of 5% per annum compounded annua [#permalink]
15 Apr 2014, 19:39

Buneul,

I have a doubt.

Quote:

The interest earned in the 1st year = $50 The interest earned in the 2nd year = $50*1.05 The interest earned in the 3rd year = $50*1.05^2 The interest earned in the 4th year = $50*1.05^3 The interest earned in the 5th year = $50*1.05^4

So we are just calculating the interest from interest.Are we not supposed to calculate the interest from the principle amount every year?

Re: A bank offers an interest of 5% per annum compounded annua [#permalink]
15 Apr 2014, 21:00

atalpanditgmat wrote:

emmak wrote:

A bank offers an interest of 5% per annum compounded annually on all its deposits. If $10,000 is deposited, what will be the ratio of the interest earned in the 4th year to the interest earned in the 5th year?

A. 1:5 B. 625:3125 C. 100:105 D. 1004:1054 E. 725:3225

Hi Bunuel, Here is my approach: is this correct?

Interest earned in 4 year= 10000(1+0.05)^4

Interest earned in 5 year= 10000(1+0.05)^5

Ratio= {10000(1.05)^4}/{10000(1.05^5)} =>1.05^4/1.05^5 =>1/1.05 Multiplied by 100 in both numerator and denominator gives 100:105

Hence Ans:C

This formula is to calculate the total amount, not the compound interest

You require to subtract the Principal to get the resultant compound interest

We require to calculate ratio of interest earned in 4th & 5th year

This method you're using is calculating ratio of 4 yr deposit to 5 yr deposit _________________

Re: A bank offers an interest of 5% per annum compounded annua [#permalink]
15 Apr 2014, 21:06

Bunuel wrote:

emmak wrote:

A bank offers an interest of 5% per annum compounded annually on all its deposits. If $10,000 is deposited, what will be the ratio of the interest earned in the 4th year to the interest earned in the 5th year?

A. 1:5 B. 625:3125 C. 100:105 D. 1004:1054 E. 725:3225

The interest earned in the 1st year = $50 The interest earned in the 2nd year = $50*1.05 The interest earned in the 3rd year = $50*1.05^2 The interest earned in the 4th year = $50*1.05^3 The interest earned in the 5th year = $50*1.05^4

Re: A bank offers an interest of 5% per annum compounded annua [#permalink]
23 Jul 2014, 08:42

A bank offers an interest of 5% per annum compounded annually on all its deposits. If $10,000 is deposited, what will be the ratio of the interest earned in the 4th year to the interest earned in the 5th year?

a) 1:5 b) 625 : 3125 c) 100 : 105 d) 100^4 : 100^5 e) 725 : 3225

First year: 10,000+5 NOTE: Using fractions is typically the easiest way to calculate, so we’ll represent 5% as 1/20 from here on out.

Second year: 10,000∗21/20+1/20∗(10,000∗21/20)=21/20(10,000∗21/20)=(21/20)2∗10,000 Third year: (21/20)2(10,000)+1/20∗(21/20)2(10,000)=21/20∗(21/20)2(10,000)=(21/20)3∗10,000) If you follow the pattern, the total value at the end of each year will simply be (21/20)n(10,000) at the end of the nth year. The amount of interest each year is 1/20 of the previous year’s balance (that …+1/20 * the previous year). So, the amount of interest calculated in the 4th year will be:

1/20∗(21/20)3(10,000) And the amount of interest earned in the 5th year will be:

1/20∗(21/20)4(10,000) Putting those into ratio, you’ll see that the 1/20 and the 10,000 is common to both, so those terms divide out, leaving simply:

(21/20)3/(21/20)4 Factoring out the common (21/20)3 term, we’re left with 1/(21/20). Dividing by a fraction is the same as multiplying by the reciprocal, so that can be expressed as 20/21, which is the same as 100/105.

MY CONFUSION : IT WAS A LONG WORDY EXPLANATION, AND I GOT LOST IN IT, SO I NEED A MORE CONCISE EXPLANATION IF POSSIBLE, ALSO WHERE DOES THE 21/ 20 COME FROM? IN SECOND YEAR HOW COME WE ARE ADDING 21/20 AND 1/20 AND THEN MULTIPLYING BY 10,000 AND 1/20 WHY NOT MULTIPLY BY 21/20?

Re: A bank offers an interest of 5% per annum compounded annua [#permalink]
23 Jul 2014, 08:47

Expert's post

sagnik2422 wrote:

A bank offers an interest of 5% per annum compounded annually on all its deposits. If $10,000 is deposited, what will be the ratio of the interest earned in the 4th year to the interest earned in the 5th year?

a) 1:5 b) 625 : 3125 c) 100 : 105 d) 100^4 : 100^5 e) 725 : 3225

First year: 10,000+5 NOTE: Using fractions is typically the easiest way to calculate, so we’ll represent 5% as 1/20 from here on out.

Second year: 10,000∗21/20+1/20∗(10,000∗21/20)=21/20(10,000∗21/20)=(21/20)2∗10,000 Third year: (21/20)2(10,000)+1/20∗(21/20)2(10,000)=21/20∗(21/20)2(10,000)=(21/20)3∗10,000) If you follow the pattern, the total value at the end of each year will simply be (21/20)n(10,000) at the end of the nth year. The amount of interest each year is 1/20 of the previous year’s balance (that …+1/20 * the previous year). So, the amount of interest calculated in the 4th year will be:

1/20∗(21/20)3(10,000) And the amount of interest earned in the 5th year will be:

1/20∗(21/20)4(10,000) Putting those into ratio, you’ll see that the 1/20 and the 10,000 is common to both, so those terms divide out, leaving simply:

(21/20)3/(21/20)4 Factoring out the common (21/20)3 term, we’re left with 1/(21/20). Dividing by a fraction is the same as multiplying by the reciprocal, so that can be expressed as 20/21, which is the same as 100/105.

MY CONFUSION : IT WAS A LONG WORDY EXPLANATION, AND I GOT LOST IN IT, SO I NEED A MORE CONCISE EXPLANATION IF POSSIBLE, ALSO WHERE DOES THE 21/ 20 COME FROM? IN SECOND YEAR HOW COME WE ARE ADDING 21/20 AND 1/20 AND THEN MULTIPLYING BY 10,000 AND 1/20 WHY NOT MULTIPLY BY 21/20?

Merging topics. Please refer to the discussion above.

Re: A bank offers an interest of 5% per annum compounded annua [#permalink]
03 Sep 2014, 22:12

Temurkhon wrote:

question ask what is:

10000*1.05^4/10000*1.05^5

we get 10000/10000*1.05=10000/10500=100/105

Hello.

You're correct for choosing C but wrong for interest formula buddy.

The question asks you to calculate ration of the interest earned in 4th year to the interest earned in 5th year. Your formula is to calculate Total value in 4th year and 5th year NOT interests.

In order to calculate INTEREST in 4th and 5th year, you have to calculate INTEREST in 1st year.

interest in 1st year = 10,000*0.05 = 500 interest in 2nd year = 500*1.05 interest in 3rd year = 500*1.05^2 interest in 4th year = 500*1.05^3 interest in 5th year = 500*1.05^4

Ratio = 1/1.05 = 100/105

Hope it helps. _________________

Please +1 KUDO if my post helps. Thank you.

"Designing cars consumes you; it has a hold on your spirit which is incredibly powerful. It's not something you can do part time, you have do it with all your heart and soul or you're going to get it wrong."

Chris Bangle - Former BMW Chief of Design.

gmatclubot

Re: A bank offers an interest of 5% per annum compounded annua
[#permalink]
03 Sep 2014, 22:12

Hey, Last week I started a few new things in my life. That includes shifting from daily targets to weekly targets, 45 minutes of exercise including 15 minutes of yoga, making...

This week went in reviewing all the topics that I have covered in my previous study session. I reviewed all the notes that I have made and started reviewing the Quant...

I started running as a cross country team member since highshcool and what’s really awesome about running is that...you never get bored of it! I participated in...