GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 15 Dec 2018, 13:07

### 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

## Events & Promotions

###### Events & Promotions in December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
• ### $450 Tuition Credit & Official CAT Packs FREE December 15, 2018 December 15, 2018 10:00 PM PST 11:00 PM PST Get the complete Official GMAT Exam Pack collection worth$100 with the 3 Month Pack ($299) • ### FREE Quant Workshop by e-GMAT! December 16, 2018 December 16, 2018 07:00 AM PST 09:00 AM PST Get personalized insights on how to achieve your Target Quant Score. # The amount of an investment will double in approximately 70/ p years,  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics Author Message TAGS: ### Hide Tags Math Expert Joined: 02 Sep 2009 Posts: 51218 The amount of an investment will double in approximately 70/ p years, [#permalink] ### Show Tags 27 Dec 2015, 08:53 1 4 00:00 Difficulty: 35% (medium) Question Stats: 71% (01:51) correct 29% (02:31) wrong based on 118 sessions ### HideShow timer Statistics The amount of an investment will double in approximately 70/ p years, where p is the percent interest, compounded annually. If Thelma invests$ 40,000 in a long-term CD that pays 5 percent interest, compounded annually, what will be the approximate total value of the investment when Thelma is ready to retire 42 years later?

A. $280,000 B.$ 320,000
C. $360,000 D.$ 450,000
E. $540,000 _________________ Current Student Joined: 18 Sep 2014 Posts: 228 Re: The amount of an investment will double in approximately 70/ p years, [#permalink] ### Show Tags 27 Dec 2015, 08:59 2 1 The amount of an investment will double in approximately 70/ p years, where p is the percent interest, compounded annually. If Thelma invests$ 40,000 in a long-term CD that pays 5 percent interest, compounded annually, what will be the approximate total value of the investment when Thelma is ready to retire 42 years later?

The investment gets doubled in 70/p years. Therefore, the investment gets doubled in 70/5= every 14 years. After 42 years, the investment will get doubled 42/14= 3 times.

So the amount invested will get doubled thrice.
So, 40000 *2 = 80000
80000*2 = 160000
160000*2 = 320000

_________________

Kindly press the Kudos to appreciate my post !!

EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 13087
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: The amount of an investment will double in approximately 70/ p years,  [#permalink]

### Show Tags

30 Dec 2015, 10:35
1
Hi All,

This question is a 'lift' of a question in the recent OGs:

PS Question #141 (page 172) in the OG13 and GMAT2015
PS Question #166 (page 166) in the GMAT 2016

GMAT assassins aren't born, they're made,
Rich
_________________

760+: Learn What GMAT Assassins Do to Score at the Highest Levels
Contact Rich at: Rich.C@empowergmat.com

# Rich Cohen

Co-Founder & GMAT Assassin

Special Offer: Save $75 + GMAT Club Tests Free Official GMAT Exam Packs + 70 Pt. Improvement Guarantee www.empowergmat.com/ *****Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***** Senior SC Moderator Joined: 22 May 2016 Posts: 2211 The amount of an investment will double in approximately 70/ p years, [#permalink] ### Show Tags 25 Dec 2017, 12:56 1 Bunuel wrote: The amount of an investment will double in approximately 70/ p years, where p is the percent interest, compounded annually. If Thelma invests$ 40,000 in a long-term CD that pays 5 percent interest, compounded annually, what will be the approximate total value of the investment when Thelma is ready to retire 42 years later?

A. $280,000 B.$ 320,000
C. $360,000 D.$ 450,000
E. $540,000 This question can be done in simple steps. 1) Find the number of years investment will double in this case. Use the formula, with interest rate, p = 5 percent Doubling = $$\frac{70}{p}$$ years Doubling = $$\frac{70}{5}$$years = 14 years to double 2) In the longer span of 42 years, how many times will investment double? $$\frac{TotalYears}{YrsToDouble}$$ = # of times the money will double $$\frac{42}{14}=$$ 3 times that the money will double 3) Total at the end? Money doubles (*2) three times: $$(2)(2)(2) = 2^3$$ $$(40,000 * 2^3) = (40,000*8) = 320,000$$ OR, very simply:$40,000 Start
+14 yrs =
$80,000 +14 yrs =$160,000
+14 yrs =
\$320,000 End

The amount of an investment will double in approximately 70/ p years, &nbs [#permalink] 25 Dec 2017, 12:56
Display posts from previous: Sort by