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:

On May 1 of last year, Jasmin invested x dollars in a new [#permalink]
05 Jun 2012, 04:03

00:00

A

B

C

D

E

Difficulty:

15% (low)

Question Stats:

83% (01:43) correct
17% (00:58) wrong based on 130 sessions

On May 1 of last year, Jasmin invested x dollars in a new account at an interest rate of 6 percent per year, compounded monthly. If no other deposits or withdrawals were made in the account and the interest rate did not change, what is the value of x?

(1) As of June1 of last year, the investment had earned $200 in interest. (2) As of July 1 of last year, the investment had earned $401 in interest.

I got this right but it was the guess work, Can someone please explain the mathematical solution to this?

Re: On May 1 of last year, Jasmin invested x dollars in a new [#permalink]
05 Jun 2012, 08:32

I think you can just use the formula: Future Value = Present Value x (1 + (interest rate/12))^number of months

In both cases, they give you Future Value (Present Value + Interest Earned), they give you the interest rate (6.0% annually), and they give you the number of months to compound over, so you can solve for the Present Value in both cases

(1) As of June1 of last year, the investment had earned $200 in interest.

In one months time, the interest earned is $200:

x * (\frac{0.5}{100}) = 200.

From this, we can find out the value of x. Hence, A is sufficient

(2) As of July 1 of last year, the investment had earned $401 in interest.

In two months, the interest earned on the new principal is $401:

x * (1 + \frac{0.5}{100})*(\frac{0.5}{100}) = 401.

Above, the expression x * (1 + \frac{0.5}{100}) represents the principal after the end if the first month i.e the initial principal+one month's worth of interest. This is enough to compute the value of x. B is also sufficient.

Thus, the answer is D, both statements alone are sufficient.

on may 1 of last year, jasmin invested X dollars in a new ac [#permalink]
16 Jan 2013, 22:29

1

This post received KUDOS

on may 1 of last year, jasmin invested X dollars in a new account at an interest rate of 6 percent per year, compounded monthly. If no other deposits or withdrawals were made in the account and the interest rate did not change, what is the value of x?

1) as of june 1 of last year, the investment had earned $200 in interest 2) as of july 1 of lasy year, the investment had earned $401 in interest.

I know its a basic question, you don't really need to solve it but I'm interested in the detailed approach in case I see a problem solving question of this type. _________________

Re: on may 1 of last year, jasmin invested X dollars in a new ac [#permalink]
17 Jan 2013, 00:35

fozzzy wrote:

on may 1 of last year, jasmin invested X dollars in a new account at an interest rate of 6 percent per year, compounded monthly. If no other deposits or withdrawals were made in the account and the interest rate did not change, what is the value of x?

1) as of june 1 of last year, the investment had earned $200 in interest 2) as of july 1 of lasy year, the investment had earned $401 in interest.

I know its a basic question, you don't really need to solve it but I'm interested in the detailed approach in case I see a problem solving question of this type.

Re: on may 1 of last year, jasmin invested X dollars in a new ac [#permalink]
17 Jan 2013, 00:48

2

This post received KUDOS

Expert's post

fozzzy wrote:

on may 1 of last year, jasmin invested X dollars in a new account at an interest rate of 6 percent per year, compounded monthly. If no other deposits or withdrawals were made in the account and the interest rate did not change, what is the value of x?

1) as of june 1 of last year, the investment had earned $200 in interest 2) as of july 1 of lasy year, the investment had earned $401 in interest.

I know its a basic question, you don't really need to solve it but I'm interested in the detailed approach in case I see a problem solving question of this type.

Statement 1-

Monthly C.I.(Compd. Int.) = 6/12=0.5% per month; When there is only one period for calculation, then C.I.= S.I.(simple Int.). In this question May to June is one month only.

We know that SI=P*r*t/100 => 200=P*0.5*1/100 => P can be derived. There is no need to calculate exact value in DS question.Just make sure there is a unique value. Sufficient.

Statement 2-

From May to July there are 2 periods, so this is the case of CI rather SI.

We know that CI=P(1+r/100)^n => n= # of periods = 2 months => 401=P(1+0.5/100)^2 => P can be derived. There is no need to calculate exact value. Sufficient.

Answer D.

-Shalabh Jain _________________

Learn how eGMATers improved their GMAT scores by 100+ points - Click here

Learn about our newly released Quant Online course here.

Re: on may 1 of last year, jasmin invested X dollars in a new ac [#permalink]
17 Jan 2013, 03:23

Expert's post

fozzzy wrote:

on may 1 of last year, jasmin invested X dollars in a new account at an interest rate of 6 percent per year, compounded monthly. If no other deposits or withdrawals were made in the account and the interest rate did not change, what is the value of x?

1) as of june 1 of last year, the investment had earned $200 in interest 2) as of july 1 of lasy year, the investment had earned $401 in interest.

I know its a basic question, you don't really need to solve it but I'm interested in the detailed approach in case I see a problem solving question of this type.

Re: On May 1 of last year, Jasmin invested x dollars in a new [#permalink]
25 Mar 2013, 15:04

I thought with monthly compounding interest, your time value must be multiplied by 12? But we are getting 1 as the exponent, is this because you are multiplying 12* 1/12 for the number of periods being just one month?

Re: on may 1 of last year, jasmin invested X dollars in a new ac [#permalink]
25 Mar 2013, 15:10

PraPon wrote:

Interest Rate per month: 6%/12 months = 0.5% (monthly)

(1) As of June1 of last year, the investment had earned $200 in interest. SUFFICIENT: interest earned in one month = $200

Principal * (0.5/100) = 200

Principal amount = $40000. Hence sufficient.

(2) As of July 1 of last year, the investment had earned $401 in interest. SUFFICIENT: interest earned in two months = $401

Principal * (1 + 0.5/100)*(0.5/100) = 401 We can solve this equation to find out Principal amount. Hence sufficient.

Hence choice(D) is the answer.

Also can you explain how you are able to get to principal * (0.5/100) = 200? I guess I am trying to go by the formula which is x(1 + (6/100) / 12) ^ n - x but i dont understand how you get to that

Re: On May 1 of last year, Jasmin invested x dollars in a new [#permalink]
12 Jan 2014, 03:14

enigma123 wrote:

On May 1 of last year, Jasmin invested x dollars in a new account at an interest rate of 6 percent per year, compounded monthly. If no other deposits or withdrawals were made in the account and the interest rate did not change, what is the value of x?

(1) As of June1 of last year, the investment had earned $200 in interest. (2) As of July 1 of last year, the investment had earned $401 in interest.

I got this right but it was the guess work, Can someone please explain the mathematical solution to this?

We're given X*0.05 = Interest after 1 month, so we have two unknowns (because even if we have more than 1 period, that's just an exponential relationship, and the exponent is never unknown)..

Isn't it simply easier to solve this like an algebraic translation instead of doing calculations? That way you only need to know what you need, not what the actual results are.

1) Solves for one of our unknowns, so it's clearly sufficient

2) Also solves for the same unknown as 1), but this time with a different exponent, so this is also sufficient.

So, answer is D. We can solve questions like these in 20 seconds with this approach, no calculation involved at all.

gmatclubot

Re: On May 1 of last year, Jasmin invested x dollars in a new
[#permalink]
12 Jan 2014, 03:14

I´ve done an interview at Accepted.com quite a while ago and if any of you are interested, here is the link . I´m through my preparation of my second...

It has been a good week so far. After the disappointment with my GMAT score, I have started to study again, re-schedule the new test date and talked with...

It’s here. Internship season. The key is on searching and applying for the jobs that you feel confident working on, not doing something out of pressure. Rotman has...