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

It is currently 14 Aug 2018, 14:59

Close

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
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.

Close

Request Expert Reply

Confirm Cancel

M21-27

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 47898
M21-27  [#permalink]

Show Tags

New post 16 Sep 2014, 01:15
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

72% (01:10) correct 28% (00:57) wrong based on 112 sessions

HideShow timer Statistics

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 47898
Re M21-27  [#permalink]

Show Tags

New post 16 Sep 2014, 01:15
1
2
Official Solution:

Between 10:06 and 12:30 the hour hand of the clock turns by

A. 66 degrees
B. 70 degrees
C. 72 degrees
D. 75 degrees
E. 78 degrees


In one hour an hour hand turns by \(\frac{360^{\circ}}{12}=30^{\circ}\).

Since the difference between 10:06 and 12:30 is \(2\frac{2}{5}\) hours then in that time the hour hand of the clock turns by \(30^{\circ}*2\frac{2}{5}=72^{\circ}\).


Answer: C
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Senior Manager
Senior Manager
User avatar
Status: Math is psycho-logical
Joined: 07 Apr 2014
Posts: 421
Location: Netherlands
GMAT Date: 02-11-2015
WE: Psychology and Counseling (Other)
Re: M21-27  [#permalink]

Show Tags

New post 21 Jan 2015, 08:20
Hi Bunuel,

Thank you for this explanaton.
I would like to propose another solution, and you can tell me if it is useful or not and/or perhaps add your comments on it.

So, what I thought and led me to the correct solution is that the hour hand would make 2 full revolutions: one from 10.06 to 11.06 and one from 11.06 to 12.06.

Then, there are some minutes left, but the hour hand would remain at the same hour (even though the degree would change).

So, what I did was 360*2 = 720, and chose ANS C.

Is there some valid reasoning that led me to the correct answer? Because I am definitely missing sth!
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 47898
Re: M21-27  [#permalink]

Show Tags

New post 21 Jan 2015, 08:50
pacifist85 wrote:
Hi Bunuel,

Thank you for this explanaton.
I would like to propose another solution, and you can tell me if it is useful or not and/or perhaps add your comments on it.

So, what I thought and led me to the correct solution is that the hour hand would make 2 full revolutions: one from 10.06 to 11.06 and one from 11.06 to 12.06.

Then, there are some minutes left, but the hour hand would remain at the same hour (even though the degree would change).

So, what I did was 360*2 = 720, and chose ANS C.

Is there some valid reasoning that led me to the correct answer? Because I am definitely missing sth!


Have you read the solution above? The correct answer is 72 degrees, your answer is 720 degrees, which is obviously not correct. In 1 hour the hour hand does NOT make one full revolution, the minute hand does...
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Senior Manager
Senior Manager
User avatar
Status: Math is psycho-logical
Joined: 07 Apr 2014
Posts: 421
Location: Netherlands
GMAT Date: 02-11-2015
WE: Psychology and Counseling (Other)
Re: M21-27  [#permalink]

Show Tags

New post 21 Jan 2015, 09:06
Hi Bunuel,

Thank you for responding. Yes I did read your solution and I find it very useful, as I said. Thank you.

The reason why I asked whether what I did was reasonable, was exactly because my response was 720 and NOT 72, which is the wrong response obiously, but there could be a connection as 720 is 10*72. I just wanted to see if there was a justification for that or not.

Because only the fact that I got 720, and not 660, 700 or any of the other values in the answer options, or any other random value for that matter, led me to respond C, which happens to be the right answer.. So, I wanted to understand my mistake.
Current Student
User avatar
Joined: 12 Aug 2015
Posts: 291
Concentration: General Management, Operations
GMAT 1: 640 Q40 V37
GMAT 2: 650 Q43 V36
GMAT 3: 600 Q47 V27
GPA: 3.3
WE: Management Consulting (Consulting)
Re: M21-27  [#permalink]

Show Tags

New post 07 Feb 2016, 05:33
The time from 10:06 to 12:30 equals 144 minutes. There are 12 total hours (or 12*60 minutes) on the clock hence 360 degrees. Therefore

144/(12*60) = 1/5 of 360 degrees = 72 degrees
_________________

KUDO me plenty

Intern
Intern
avatar
B
Joined: 10 May 2017
Posts: 27
Re: M21-27  [#permalink]

Show Tags

New post 10 Jun 2017, 02:06
I solved in a way different manner I suppose.

10:06 to 12:06 - 60 degrees

for next 24 mins the hour hand will move by (24 x 6 x 30)/360=12

So 60+12=72 degrees.

Not sure if this is easy way though.
Director
Director
User avatar
S
Joined: 08 Jun 2015
Posts: 529
Location: India
GMAT 1: 640 Q48 V29
GMAT 2: 700 Q48 V38
Premium Member CAT Tests
Re: M21-27  [#permalink]

Show Tags

New post 08 Dec 2017, 03:37
In one minute the hour hand moves by 0.5 degrees. From 10:06 to 12:30 , the hour hand moves by 144 minutes or 2 hours 24 min. Hence the hour hand will move by 72 degrees between 10:06 and 12:30.

Option C
_________________

" The few , the fearless "

Re: M21-27 &nbs [#permalink] 08 Dec 2017, 03:37
Display posts from previous: Sort by

M21-27

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  

Moderators: chetan2u, Bunuel

Events & Promotions

PREV
NEXT


GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.