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

 It is currently 14 Nov 2018, 09:46

# Join Chat Room for Live Updates

### 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 November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
• ### $450 Tuition Credit & Official CAT Packs FREE November 15, 2018 November 15, 2018 10:00 PM MST 11:00 PM MST EMPOWERgmat is giving away the complete Official GMAT Exam Pack collection worth$100 with the 3 Month Pack ($299) • ### Free GMAT Strategy Webinar November 17, 2018 November 17, 2018 07:00 AM PST 09:00 AM PST Nov. 17, 7 AM PST. Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT. # On a scale that measures the intensity of a certain phenomen  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics Author Message TAGS: ### Hide Tags Senior Manager Joined: 28 Jul 2011 Posts: 364 Location: United States Concentration: International Business, General Management GPA: 3.86 WE: Accounting (Commercial Banking) On a scale that measures the intensity of a certain phenomen [#permalink] ### Show Tags Updated on: 07 Dec 2012, 05:35 6 56 00:00 Difficulty: 25% (medium) Question Stats: 74% (01:07) correct 26% (01:33) wrong based on 2021 sessions ### HideShow timer Statistics On a scale that measures the intensity of a certain phenomenon, a reading of n+1 corresponds to an intensity that is 10 times the intensity corresponding to a reading of n. On that scale, the intensity corresponding to a reading of 8 is how many times as great as the intensity corresponding to a reading of 3? (A) 5 (B) 50 (C) 10^5 (D) 5^10 (E) 8^10 - 3^10 _________________ +1 Kudos If found helpful.. Originally posted by mydreammba on 14 Jan 2012, 02:06. Last edited by Bunuel on 07 Dec 2012, 05:35, edited 2 times in total. Renamed the topic and edited the question. ##### Most Helpful Expert Reply Magoosh GMAT Instructor Joined: 28 Dec 2011 Posts: 4488 Re: Problem solving [#permalink] ### Show Tags 13 Mar 2013, 09:24 39 15 abusaleh wrote: Can anyone give me proper explanation of this question? On a scale that measures the intensity of a certain phenomenon, a reading of n+1 corresponds to an intensity that is 10 times the intensity corresponding to a reading of n. On that scale, the intensity corresponding to a reading of 8 is how many times as great as the intensity corresponding to a reading of 3? A) 5 B) 50 C) 10^5 D) 5^10 E) 8^10 - 3^10 Dear abusaleh, This is a tricky question. It is based on logarithmic scales --- both the Richter scale for earthquakes and the decibel scale for the volume of sound follow this pattern. It tell us if we we go from n to n+1 on the scale, the intensity is 10 times greater. Start at 3. If we go from 3 to 4 on the scale, the intensity increases 10 times. Then from 4 to 5, it increases 10 times. Same, from 5 to 6, from 6 to 7, and from 7 to 8. There are five "steps" from 3 to 8, and each one of these steps increases the intensity by a factor of 10. That means, when we go from 3 to 8 on the scale, we multiply the intensity by 10 five times ---- 10*10*10*10*10 = 10^5 Answer = C Does this make sense? Mike _________________ Mike McGarry Magoosh Test Prep Education is not the filling of a pail, but the lighting of a fire. — William Butler Yeats (1865 – 1939) ##### Most Helpful Community Reply Intern Status: ISB 14...:) Joined: 25 May 2012 Posts: 29 Location: India Concentration: Strategy Schools: ISB '14 (A) GMAT 1: 750 Q51 V39 GPA: 3.62 WE: Engineering (Energy and Utilities) Re: maths problem [#permalink] ### Show Tags 07 Jun 2012, 00:52 14 4 As the intensity increases 10 times every time from 3 to 8, it increases 5 times. So,answer is 10^5 ##### General Discussion Math Expert Joined: 02 Sep 2009 Posts: 50583 On a scale that measures the intensity of a certain phenomen [#permalink] ### Show Tags 14 Jan 2012, 03:54 18 23 kotela wrote: Hey Guys i didn't understand the solution to the problem in OG 12 PS#98, can anyone please explain me the solution??? kotela it's better to post the question itself to get prompt replies. I guess you are talking about the following question: On a scale that measures the intensity of a certain phenomenon, a reading of n+1 corresponds to an intensity that is 10 times the intensity corresponding to a reading of n. On that scale, the intensity corresponding to a reading of 8 is how many times as great as the intensity corresponding to a reading of 3? A. 5 B. 50 C. 10^5 D. 5^10 E. 8^10 - 3^10 Basically we are given that each number on the scale is 10 times the previous number. For example: If reading of n=3 is 5 then the reading of n=4 would be 5*10 --> the reading of n=5 would be 5*10^2 --> the reading of n=6 would be 5*10^3. Therefore the reading of 8 will be 10^5 times as great as the reading of 3 (the power of 10 goes up by 1 for each step in reading and as there are 5 steps from 3 to 8 then the reading of 8 will be 10^5 times as great as the reading of 3). Or think about it this way: we have functional relationship: when we increase the reading by 1 the intensity increases 10 times the previous one: $$f(n+1)=10*f(n)$$. So if $$f(3)=x$$, then $$f(4)=10*f(3)=10x$$ and so on. Therefore $$f(8)=10^5*f(3)$$. Answer: C. Hope it's clear. _________________ Senior Manager Joined: 28 Jul 2011 Posts: 364 Location: United States Concentration: International Business, General Management GPA: 3.86 WE: Accounting (Commercial Banking) Re: OG12 PS#98 [#permalink] ### Show Tags 14 Jan 2012, 06:28 Bunuel wrote: kotela wrote: Hey Guys i didn't understand the solution to the problem in OG 12 PS#98, can anyone please explain me the solution??? kotela it's better to post the question itself to get prompt replies. I guess you are talking about the following question: On a scale that measures the intensity of a certain phenomenon, a reading of n+1 corresponds to an intensity that is 10 times the intensity corresponding to a reading of n. On that scale, the intensity corresponding to a reading of 8 is how many times as great as the intensity corresponding to a reading of 3? A. 5 B. 50 C. 10^5 D. 5^10 E. 8^10 - 3^10 Basically we are given that each number on the scale is 10 times the previous number. For example: If reading of n=3 is 5 then the reading of n=4 would be 5*10 --> the reading of n=5 would be 5*10^2 --> the reading of n=6 would be 3*10^3. Therefore the reading of 8 will be 10^5 times as great as the reading of 3 (the power of 10 goes up by 1 for each step in reading and as there are 5 steps from 3 to 8 then the reading of 8 will be 10^5 times as great as the reading of 3). Or think about it this way: we have functional relationship: when we increase the reading by 1 the intensity increases 10 times the previous one: $$f(n+1)=10*f(n)$$. So if $$f(3)=x$$, then $$f(4)=10*f(3)=10x$$ and so on. Therefore $$f(8)=10^5*f(3)$$. Answer: C. Hope it's clear. Thanks a lot.....I will _________________ +1 Kudos If found helpful.. Intern Joined: 12 May 2012 Posts: 19 Location: United States Concentration: Technology, Human Resources Re: maths problem [#permalink] ### Show Tags 07 Jun 2012, 01:09 gnan wrote: As the intensity increases 10 times every time from 3 to 8, it increases 5 times. So,answer is 10^5 thanks a lot that was very helpful VP Status: Far, far away! Joined: 02 Sep 2012 Posts: 1073 Location: Italy Concentration: Finance, Entrepreneurship GPA: 3.8 Re: Problem solving [#permalink] ### Show Tags 13 Mar 2013, 12:13 2 1 We know that: $$f(n+1)=10f(n)$$ so $$f(8)=10f(7)$$ , $$f(7)=10f(6)$$ and so on... $$f(8)=10*10*10*10*10f(3)$$ Each 10 represents a "step back" _________________ It is beyond a doubt that all our knowledge that begins with experience. Kant , Critique of Pure Reason Tips and tricks: Inequalities , Mixture | Review: MGMAT workshop Strategy: SmartGMAT v1.0 | Questions: Verbal challenge SC I-II- CR New SC set out !! , My Quant Rules for Posting in the Verbal Forum - Rules for Posting in the Quant Forum[/size][/color][/b] Intern Joined: 04 Jun 2014 Posts: 2 Re: On a scale that measures the intensity of a certain phenomen [#permalink] ### Show Tags 19 Jul 2014, 01:47 3 1 A soln. easy to understand- For n=3, consider the intensity to be x. For n+1 = 4 , we have [intensity*10 ]= 10x For n+2 = 5 , we have [10x*10 ]= 100x For n+3 = 6 , we have [100x*10 ]= 1000x For n+4 = 7 , we have [1000x*10 ]= 10000x For n+5 = 8 , we have [10000x*10 ]= 100000x Now , for n = 8 -->100000x = 10^5 x which is 10^5 times x, the original intensity at n=3 Manager Joined: 10 Jun 2015 Posts: 118 Re: On a scale that measures the intensity of a certain phenomen [#permalink] ### Show Tags 14 Aug 2015, 02:23 1 mydreammba wrote: On a scale that measures the intensity of a certain phenomenon, a reading of n+1 corresponds to an intensity that is 10 times the intensity corresponding to a reading of n. On that scale, the intensity corresponding to a reading of 8 is how many times as great as the intensity corresponding to a reading of 3? (A) 5 (B) 50 (C) 10^5 (D) 5^10 (E) 8^10 - 3^10 n = 10^(n-1)*k , where n=1,2,3,....... 8 = 10^7*k 3 = 10^2*k It implies 8 is 10^5 times of 3 Senior Manager Joined: 15 Oct 2015 Posts: 322 Concentration: Finance, Strategy GPA: 3.93 WE: Account Management (Education) Re: On a scale that measures the intensity of a certain phenomen [#permalink] ### Show Tags 28 Feb 2016, 10:27 mydreammba wrote: On a scale that measures the intensity of a certain phenomenon, a reading of n+1 corresponds to an intensity that is 10 times the intensity corresponding to a reading of n. On that scale, the intensity corresponding to a reading of 8 is how many times as great as the intensity corresponding to a reading of 3? (A) 5 (B) 50 (C) 10^5 (D) 5^10 (E) 8^10 - 3^10 According to Manhattan-Gmat, the GMAT is a test of foreign language. Any reading is 10 times the previous reading, if the reading is increasing by 1. Target Test Prep Representative Status: Head GMAT Instructor Affiliations: Target Test Prep Joined: 04 Mar 2011 Posts: 2830 Re: On a scale that measures the intensity of a certain phenomen [#permalink] ### Show Tags 02 May 2016, 06:18 mydreammba wrote: On a scale that measures the intensity of a certain phenomenon, a reading of n+1 corresponds to an intensity that is 10 times the intensity corresponding to a reading of n. On that scale, the intensity corresponding to a reading of 8 is how many times as great as the intensity corresponding to a reading of 3? (A) 5 (B) 50 (C) 10^5 (D) 5^10 (E) 8^10 - 3^10 To solve this problem we need to examine the information in the first sentence. We are told that “a reading of n + 1 corresponds to an intensity that is 10 times the intensity corresponding to a reading of n.” Let’s practice this idea with some real numbers. Let’s say n is 2. This means that n + 1 = 3. With the information we were given we can say that a reading of 3 is ten times as great as the intensity of a reading of 2. Furthermore, we can say that a reading of 4 is actually 10 x 10 = 10^2 times as great as the intensity of a reading of 2. Increasing one more unit, we can say that a reading of 5 is 10 x 10 x 10 = 10^3 times as great as the intensity of a reading of 2. We have found a pattern, which can be applied to the problem presented in the stem: 3 is “one” unit away from 2, and thus a reading of 3 is 10^1 times as great as the intensity of a reading of 2. 4 is “two” units away from 2, and thus a reading of 4 is 10^2 times as great as the intensity of a reading of 2. 5 is “three” units away from 2, and thus a reading of 5 is 10^3 times as great as the intensity of a measure of 2. We can use this pattern to easily answer the question. Here we are being asked for the number of times the intensity corresponding to a reading of 8 is as great as the intensity corresponding to a reading of 3. Because 8 is 5 units greater than 3, a reading of 8 is 10^5 times as great as the intensity corresponding to a reading of 3. Answer C. _________________ Jeffery Miller Head of GMAT Instruction GMAT Quant Self-Study Course 500+ lessons 3000+ practice problems 800+ HD solutions Manager Joined: 22 May 2015 Posts: 104 Re: On a scale that measures the intensity of a certain phenomen [#permalink] ### Show Tags 20 Mar 2017, 06:17 From question n+1 = N * 10 say the readings are 1,10,100,1000,10^4,10^5 so on... Implies it is 5 times greater _________________ Consistency is the Key Senior Manager Status: Come! Fall in Love with Learning! Joined: 05 Jan 2017 Posts: 489 Location: India Re: On a scale that measures the intensity of a certain phenomen [#permalink] ### Show Tags 21 Mar 2017, 03:12 mydreammba wrote: On a scale that measures the intensity of a certain phenomenon, a reading of n+1 corresponds to an intensity that is 10 times the intensity corresponding to a reading of n. On that scale, the intensity corresponding to a reading of 8 is how many times as great as the intensity corresponding to a reading of 3? (A) 5 (B) 50 (C) 10^5 (D) 5^10 (E) 8^10 - 3^10 we can say that f(n) = 10^n f(8)/ f(3) = 10^8/10^3 = 10^5 _________________ GMAT Mentors Director Joined: 02 Sep 2016 Posts: 689 Re: On a scale that measures the intensity of a certain phenomen [#permalink] ### Show Tags 02 Apr 2017, 23:05 The intensity of 3 is n. 8-3= 5 Therefore the intensity of 8 will be 5 times the intensity of 3. Therefore the answer is 10^5. _________________ Help me make my explanation better by providing a logical feedback. If you liked the post, HIT KUDOS !! Don't quit.............Do it. Manager Joined: 30 Apr 2013 Posts: 81 Re: On a scale that measures the intensity of a certain phenomen [#permalink] ### Show Tags 24 Aug 2017, 23:16 what level question is this? Math Expert Joined: 02 Sep 2009 Posts: 50583 Re: On a scale that measures the intensity of a certain phenomen [#permalink] ### Show Tags 24 Aug 2017, 23:18 santro789 wrote: what level question is this? You can check difficulty level of a question along with the stats on it in the first post. For this question Difficulty: 600-700 Level. _________________ Intern Joined: 22 Oct 2017 Posts: 31 Re: On a scale that measures the intensity of a certain phenomen [#permalink] ### Show Tags 02 Dec 2017, 04:42 Honestly this question is very confusing for me. Based on the question stem I cannot recognize that the intensity increases 10 times every time... EMPOWERgmat Instructor Status: GMAT Assassin/Co-Founder Affiliations: EMPOWERgmat Joined: 19 Dec 2014 Posts: 12853 Location: United States (CA) GMAT 1: 800 Q51 V49 GRE 1: Q170 V170 Re: On a scale that measures the intensity of a certain phenomen [#permalink] ### Show Tags 05 Mar 2018, 12:03 1 Hi All, The logic behind this question is similar to how earthquakes are measured, but you don't need to recognize that to answer the question correctly. Like many questions on the Quant section, this question needs to be "played with" a bit. We're told that with each "+1" increase in the "level of intensity" on a scale, the intensity of a phenomenon increases 10 times. So, for example: Level 1 = Z intensity Level 2 = 10Z intensity Level 3 = 100Z intensity Level 4 = 1,000Z intensity Etc. We're asked how many TIMES greater "level 8" is than "level 3", so I can either continue on with the table or use "exponent math" The table…. Level 3 = 100Z Level 4 = 1,000Z Level 5 = 10,00Z Level 6 = 100,000Z Level 7 = 1,000,000Z Level 8 = 10,000,000Z Level 8/Level 3 = 10,000,000Z/100Z = 10,000 times greater Using "exponent math", we know that every level is "10x" greater than the previous level. Since Level 8 is "5 levels" above Level 3, that would be 10^5 greater. Final Answer: 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!*****

Manager
Joined: 30 May 2018
Posts: 85
Concentration: General Management, Marketing
GMAT 1: 750 Q49 V45
GPA: 3.45
WE: Other (Retail)
Re: On a scale that measures the intensity of a certain phenomen  [#permalink]

### Show Tags

23 Sep 2018, 23:25
mikemcgarry wrote:
abusaleh wrote:
Can anyone give me proper explanation of this question?
On a scale that measures the intensity of a certain phenomenon, a reading of n+1 corresponds to an intensity that is 10 times the intensity corresponding to a reading of n. On that scale, the intensity corresponding to a reading of 8 is how many times as great as the intensity corresponding to a reading of 3?
A) 5
B) 50
C) 10^5
D) 5^10
E) 8^10 - 3^10

Dear abusaleh,
This is a tricky question. It is based on logarithmic scales --- both the Richter scale for earthquakes and the decibel scale for the volume of sound follow this pattern.

It tell us if we we go from n to n+1 on the scale, the intensity is 10 times greater.

Start at 3. If we go from 3 to 4 on the scale, the intensity increases 10 times. Then from 4 to 5, it increases 10 times. Same, from 5 to 6, from 6 to 7, and from 7 to 8. There are five "steps" from 3 to 8, and each one of these steps increases the intensity by a factor of 10. That means, when we go from 3 to 8 on the scale, we multiply the intensity by 10 five times ---- 10*10*10*10*10 = 10^5

Does this make sense?

Mike
Yeah , but whats the logic behind multiplying , why not add ?
_________________

Kudos if you agree , Comment if you don't !!!

EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 12853
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: On a scale that measures the intensity of a certain phenomen  [#permalink]

### Show Tags

24 Sep 2018, 10:33
Hi Arpitkumar,

A few posts in this thread explain how the 'math' works (including the one directly above your post) - we're told that each increase of "+1" in a 'reading' translates to a "10 TIMES" increase in intensity. Since the question asks for how many 'TIMES GREATER' one INTENSITY is than another, then we are clearly going to be using multiplication. If the question had asked for the difference one READING over another, then we would use addition.

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!*****

Re: On a scale that measures the intensity of a certain phenomen &nbs [#permalink] 24 Sep 2018, 10:33
Display posts from previous: Sort by