 It is currently 25 Nov 2020, 20:35 ### 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

#### Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here. # If 25 percent of a certain number is 1,600, what is 10 perce  Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
Founder  Joined: 18 Apr 2015
Posts: 13908
GRE 1: Q160 V160 Followers: 313

Kudos [?]: 3678 , given: 12922

If 25 percent of a certain number is 1,600, what is 10 perce [#permalink]
Expert's post 00:00

Question Stats: 100% (00:30) correct 0% (00:00) wrong based on 22 sessions
If 25 percent of a certain number is 1,600, what is 10 percent of the number?

(A) 40

(B) 400

(C) 640

(D) 1,440

(E) 4,000
[Reveal] Spoiler: OA

_________________ GRE Instructor Joined: 10 Apr 2015
Posts: 3907
Followers: 163

Kudos [?]: 4766  , given: 70

Re: If 25 percent of a certain number is 1,600, what is 10 perce [#permalink]
1
KUDOS
Expert's post
Carcass wrote:
If 25 percent of a certain number is 1,600, what is 10 percent of the number?

(A) 40
(B) 400
(C) 640
(D) 1,440
(E) 4,000

IMPORTANT: We need not actually determine the number in question.

Given: 25% of a certain number is 1600
So, we know that 50% of the number is 3200
And 500% of the number is 32000
etc.

So, let's use the same logic to approximate the correct answer:
Given: 25% of a certain number is 1600
So, 12.5% of the number is 800
And 6.25% of the number is 400

Since 25% is BETWEEN 6.25% and 12.5%, we know that the correct answer is BETWEEN 400 and 800

RELATED VIDEO FROM OUR COURSE

_________________

Brent Hanneson – Creator of greenlighttestprep.com  Manager Joined: 27 Feb 2017
Posts: 188
Followers: 1

Kudos [?]: 78  , given: 15

Re: If 25 percent of a certain number is 1,600, what is 10 perce [#permalink]
1
KUDOS
I know that this below method is not usually the preferred 'easy' way, but I have been doing like this for a while now and I could solve this in 30seconds:
Let number be x. i.e 25x/100=1600. x= (1600*100)/25=6400. (6400*10)/100= 640 Target Test Prep Representative Affiliations: Target Test Prep
Joined: 09 May 2016
Posts: 161
Location: United States
Followers: 8

Kudos [?]: 202  , given: 0

Re: If 25 percent of a certain number is 1,600, what is 10 perce [#permalink]
1
KUDOS
Expert's post
Carcass wrote:
If 25 percent of a certain number is 1,600, what is 10 percent of the number?

(A) 40

(B) 400

(C) 640

(D) 1,440

(E) 4,000

We can let n = the number in question and create the equation:

0.25n = 1,600

n = 6,400

So 10% of 6,400 is 0.1 x 6,400 = 640.

_________________

# Jeffrey Miller

Jeff@TargetTestPrep.com

See why Target Test Prep is the top rated GRE quant course on GRE Prep Club. Read Our Reviews

Director Joined: 09 Nov 2018
Posts: 505
Followers: 0

Kudos [?]: 56 , given: 1

Re: If 25 percent of a certain number is 1,600, what is 10 perce [#permalink]
GreenlightTestPrep wrote:
Since 25% is BETWEEN 6.25% and 12.5%,

Is it 25% or 10%? Founder  Joined: 18 Apr 2015
Posts: 13908
GRE 1: Q160 V160 Followers: 313

Kudos [?]: 3678  , given: 12922

Re: If 25 percent of a certain number is 1,600, what is 10 perce [#permalink]
1
KUDOS
Expert's post
Translation: 25 percent of a certain number is 1,600

$$0.25 x = 1600$$

$$x = \frac{1600}{0.25} = 6400$$

Then

$$0.1 of 6400 = 640$$

Regards
_________________
Supreme Moderator
Joined: 01 Nov 2017
Posts: 371
Followers: 12

Kudos [?]: 186 , given: 4

Re: If 25 percent of a certain number is 1,600, what is 10 perce [#permalink]
Expert's post
AE wrote:
GreenlightTestPrep wrote:
Since 25% is BETWEEN 6.25% and 12.5%,

Is it 25% or 10%?

It is a typo.. it should be 10%
_________________

Some useful Theory.
1. Arithmetic and Geometric progressions : https://greprepclub.com/forum/progressions-arithmetic-geometric-and-harmonic-11574.html#p27048
2. Effect of Arithmetic Operations on fraction : https://greprepclub.com/forum/effects-of-arithmetic-operations-on-fractions-11573.html?sid=d570445335a783891cd4d48a17db9825
3. Remainders : https://greprepclub.com/forum/remainders-what-you-should-know-11524.html
4. Number properties : https://greprepclub.com/forum/number-property-all-you-require-11518.html
5. Absolute Modulus and Inequalities : https://greprepclub.com/forum/absolute-modulus-a-better-understanding-11281.html Re: If 25 percent of a certain number is 1,600, what is 10 perce   [#permalink] 17 Jan 2019, 06:38
Display posts from previous: Sort by

# If 25 percent of a certain number is 1,600, what is 10 perce  Question banks Downloads My Bookmarks Reviews Important topics  Powered by phpBB © phpBB Group Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.