It is currently 21 Nov 2017, 22:43

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Hugo lies on top of a building, throwing pennies straight down to the

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

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42281

Kudos [?]: 132990 [0], given: 12402

Hugo lies on top of a building, throwing pennies straight down to the [#permalink]

Show Tags

New post 03 Jul 2015, 02:59
Expert's post
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

82% (01:26) correct 18% (01:17) wrong based on 79 sessions

HideShow timer Statistics

Hugo lies on top of a building, throwing pennies straight down to the street below. The formula for the height, H, that a penny falls is \(H= Vt+ 5t^2\), where V/is the original velocity o f the penny (how fast Hugo throws it when it leaves his hand) and t is equal to the time it takes to hit the ground. The building is 60 meters high, and Hugo throws the penny down at an initial speed of 20 meters per second. How long does it take for the penny to hit the ground?

A. 2/5 seconds
B. 1 second
C. 2 seconds
D. 5 seconds
E. 6 seconds

Kudos for a correct solution.
[Reveal] Spoiler: OA

_________________

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

Kudos [?]: 132990 [0], given: 12402

Manager
Manager
User avatar
Joined: 26 Dec 2011
Posts: 120

Kudos [?]: 104 [0], given: 44

Schools: HBS '18, IIMA
Re: Hugo lies on top of a building, throwing pennies straight down to the [#permalink]

Show Tags

New post 03 Jul 2015, 03:46
Bunuel wrote:
Hugo lies on top of a building, throwing pennies straight down to the street below. The formula for the height, H, that a penny falls is \(H= Vt+ 5t^2\), where V/is the original velocity o f the penny (how fast Hugo throws it when it leaves his hand) and t is equal to the time it takes to hit the ground. The building is 60 meters high, and Hugo throws the penny down at an initial speed of 20 meters per second. How long does it take for the penny to hit the ground?

A. 2/5 seconds
B. 1 second
C. 2 seconds
D. 5 seconds
E. 6 seconds

Kudos for a correct solution.


Solution -
Given that, H=60m, V=20m/s and t=?
Substitute above values in the given equation -> 60=20t+5t^2 -> t^2-2t+6t-12=0 -> (t-2)(t+6) =0

t = 2, -6. Time can not be in -ve value so ANS C.
_________________

Thanks,
Kudos Please

Kudos [?]: 104 [0], given: 44

Senior Manager
Senior Manager
avatar
Joined: 15 Sep 2011
Posts: 358

Kudos [?]: 416 [0], given: 45

Location: United States
WE: Corporate Finance (Manufacturing)
GMAT ToolKit User
Hugo lies on top of a building, throwing pennies straight down to the [#permalink]

Show Tags

New post 03 Jul 2015, 10:05
Plug each answer into the equation, \(60 = 20t + 5t^{2}\), and two is the only answer. This can be done all mentally, as well.

Answer C.

Thanks

Kudos [?]: 416 [0], given: 45

Manager
Manager
User avatar
Joined: 18 Mar 2014
Posts: 237

Kudos [?]: 83 [0], given: 175

Location: India
Concentration: Operations, Strategy
GMAT 1: 670 Q48 V35
GPA: 3.19
WE: Information Technology (Computer Software)
GMAT ToolKit User
Re: Hugo lies on top of a building, throwing pennies straight down to the [#permalink]

Show Tags

New post 03 Jul 2015, 11:21
60 = 20t + 5t^2

Now dont solve quadrtic ... better just plug options .
Option C , t= 2 is correct
_________________

Press +1 Kudos if you find this Post helpful :)

Kudos [?]: 83 [0], given: 175

Expert Post
SVP
SVP
User avatar
G
Joined: 08 Jul 2010
Posts: 1851

Kudos [?]: 2348 [0], given: 51

Location: India
GMAT: INSIGHT
WE: Education (Education)
Reviews Badge
Hugo lies on top of a building, throwing pennies straight down to the [#permalink]

Show Tags

New post 03 Jul 2015, 20:45
Bunuel wrote:
Hugo lies on top of a building, throwing pennies straight down to the street below. The formula for the height, H, that a penny falls is \(H= Vt+ 5t^2\), where V/is the original velocity o f the penny (how fast Hugo throws it when it leaves his hand) and t is equal to the time it takes to hit the ground. The building is 60 meters high, and Hugo throws the penny down at an initial speed of 20 meters per second. How long does it take for the penny to hit the ground?

A. 2/5 seconds
B. 1 second
C. 2 seconds
D. 5 seconds
E. 6 seconds

Kudos for a correct solution.


Given : \(H= Vt+ 5t^2 = t*(V+5t)\)

H = 60 m
V = 20 m/s


Checking Options

A. 2/5 seconds \(H= t*(V+5t) = (2/5)(20+5*2/5) = 44/5\) which is not equal to 60 so INCORRECT Option

B. 1 second \(H= t*(V+5t) = (1)(20+5*1) = 25\) which is not equal to 60 so INCORRECT Option

C. 2 seconds \(H= t*(V+5t) = (2)(20+5*2) = 60\) Since it matches the Given height H = 60 so CORRECT Option

D. 5 seconds
E. 6 seconds

Answer: Option C
_________________

Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION

Kudos [?]: 2348 [0], given: 51

Expert Post
Math Expert
User avatar
P
Joined: 02 Aug 2009
Posts: 5223

Kudos [?]: 5868 [0], given: 118

Hugo lies on top of a building, throwing pennies straight down to the [#permalink]

Show Tags

New post 03 Jul 2015, 20:55
Bunuel wrote:
Hugo lies on top of a building, throwing pennies straight down to the street below. The formula for the height, H, that a penny falls is \(H= Vt+ 5t^2\), where V/is the original velocity o f the penny (how fast Hugo throws it when it leaves his hand) and t is equal to the time it takes to hit the ground. The building is 60 meters high, and Hugo throws the penny down at an initial speed of 20 meters per second. How long does it take for the penny to hit the ground?

A. 2/5 seconds
B. 1 second
C. 2 seconds
D. 5 seconds
E. 6 seconds

Kudos for a correct solution.


the equation that is formed by putting values..
60=20t+5t^2..
here t has to be even integer so as to make 5t^2 a multiple of 10..
only C and E left..
Also t has to be <3 as otherwise RHS> 60 so E out
ans 2,
2 and 6 can be substituted too find the correct answer
ans C
_________________

Absolute modulus :http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

Kudos [?]: 5868 [0], given: 118

Senior Manager
Senior Manager
avatar
Joined: 27 Jul 2014
Posts: 322

Kudos [?]: 72 [0], given: 15

Schools: ISB '15
GMAT 1: 660 Q49 V30
GPA: 3.76
GMAT ToolKit User Reviews Badge
Re: Hugo lies on top of a building, throwing pennies straight down to the [#permalink]

Show Tags

New post 04 Jul 2015, 09:15
Option C correct
Placing H=60 and V=20

we get t=2,-6
2 is correct

Kudos [?]: 72 [0], given: 15

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42281

Kudos [?]: 132990 [0], given: 12402

Re: Hugo lies on top of a building, throwing pennies straight down to the [#permalink]

Show Tags

New post 06 Jul 2015, 04:56
Bunuel wrote:
Hugo lies on top of a building, throwing pennies straight down to the street below. The formula for the height, H, that a penny falls is \(H= Vt+ 5t^2\), where V/is the original velocity o f the penny (how fast Hugo throws it when it leaves his hand) and t is equal to the time it takes to hit the ground. The building is 60 meters high, and Hugo throws the penny down at an initial speed of 20 meters per second. How long does it take for the penny to hit the ground?

A. 2/5 seconds
B. 1 second
C. 2 seconds
D. 5 seconds
E. 6 seconds

Kudos for a correct solution.


MANHATTAN GMAT OFFICIAL SOLUTION:

H = Wt + 5t^2
60 = 20t+5t^2
5(t + 6)(t - 2) = 0

t = -6 or t = 2.

Since a time must be positive, discard the negative value for t.

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

Kudos [?]: 132990 [0], given: 12402

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 15562

Kudos [?]: 283 [0], given: 0

Premium Member
Re: Hugo lies on top of a building, throwing pennies straight down to the [#permalink]

Show Tags

New post 24 Oct 2017, 05:57
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Kudos [?]: 283 [0], given: 0

Re: Hugo lies on top of a building, throwing pennies straight down to the   [#permalink] 24 Oct 2017, 05:57
Display posts from previous: Sort by

Hugo lies on top of a building, throwing pennies straight down to the

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


cron

GMAT Club MBA Forum Home| About| Terms and Conditions| 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®.