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

It is currently 20 Nov 2018, 05:45

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 in November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
  • All GMAT Club Tests are Free and open on November 22nd in celebration of Thanksgiving Day!

     November 22, 2018

     November 22, 2018

     10:00 PM PST

     11:00 PM PST

    Mark your calendars - All GMAT Club Tests are free and open November 22nd to celebrate Thanksgiving Day! Access will be available from 0:01 AM to 11:59 PM, Pacific Time (USA)
  • Free lesson on number properties

     November 23, 2018

     November 23, 2018

     10:00 PM PST

     11:00 PM PST

    Practice the one most important Quant section - Integer properties, and rapidly improve your skills.

A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee

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

Hide Tags

Director
Director
User avatar
B
Joined: 10 Mar 2013
Posts: 512
Location: Germany
Concentration: Finance, Entrepreneurship
GMAT 1: 580 Q46 V24
GPA: 3.88
WE: Information Technology (Consulting)
GMAT ToolKit User
A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post Updated on: 03 Feb 2016, 21:01
7
15
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

82% (01:25) correct 18% (01:49) wrong based on 1028 sessions

HideShow timer Statistics

A certain truck uses \(\frac{1}{12}+ kv^2\) gallons of fuel per mile when its speed is v miles per hour, where k is a constant. At what speed should the truck travel so that it uses \(\frac{5}{12}\) gallon of fuel per mile?

(1) The value of k is \(\frac{1}{10800}\).
(2) When the truck travels at 30 miles per hour, it uses 1/6 gallon of fuel per mile.

_________________

When you’re up, your friends know who you are. When you’re down, you know who your friends are.

Share some Kudos, if my posts help you. Thank you !

800Score ONLY QUANT CAT1 51, CAT2 50, CAT3 50
GMAT PREP 670
MGMAT CAT 630
KAPLAN CAT 660


Originally posted by BrainLab on 19 Sep 2015, 13:26.
Last edited by Bunuel on 03 Feb 2016, 21:01, edited 2 times in total.
Renamed the topic and edited the question.
Senior Manager
Senior Manager
avatar
B
Joined: 02 Dec 2014
Posts: 381
Location: Russian Federation
Concentration: General Management, Economics
GMAT 1: 640 Q44 V33
WE: Sales (Telecommunications)
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post 11 Oct 2015, 11:24
1
1
BrainLab wrote:
A certain truck uses \(\frac{1}{12}+ kv^2\) gallons of fuel per mile when its speed is v miles per hour, where k is a constant. At what speed should the truck travel so that it uses \(\frac{5}{12}\) gallon of fuel per mile?

(1) The value of k is \(\frac{1}{10800}\).
(2) When the truck travels at 30 miles per hour, it uses gallon of fuel per mile.

The correct answer is D.
The question is (1/12)+k(v^2)=5/12 (1). V-?
From st.1 we know k hence we can find v. Sufficient
From st.2 v=30 and (1/12)+k(30^2)=1 Hence we can find k and solve equation (1). Sufficient
_________________

"Are you gangsters?" - "No we are Russians!"

Manager
Manager
User avatar
Joined: 17 Jun 2015
Posts: 216
GMAT 1: 540 Q39 V26
GMAT 2: 680 Q46 V37
GMAT ToolKit User
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post 17 Dec 2015, 10:59
Each of statement give us components to complete the equation and find the asked. This is sufficient to conclude that Each Statement is sufficient instead of finding the real values.

IMO D
_________________

Fais de ta vie un rêve et d'un rêve une réalité

Intern
Intern
avatar
Joined: 28 Feb 2015
Posts: 16
Schools: Bocconi '17 (S)
GMAT 1: 700 Q47 V39
GPA: 3.33
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post 22 Jan 2016, 00:53
Does statement (2) basically state that when driving at 30 mph, the truck uses ONE gallon per mile? Think the language set me off here
Current Student
User avatar
Joined: 06 Jan 2015
Posts: 59
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post 07 Feb 2016, 13:35
1
Consumption of fuel= 1/12+ kv^2


1. It gives you the actual value for the constant k, therefore you are able to find v from the original question. SUFFICIENT
2. It gives you: 1/6 = 1/12+ k30^2 , therefore you could find k and the use this to find v. SUFFICIENT

ANSWER D




BrainLab wrote:
A certain truck uses \(\frac{1}{12}+ kv^2\) gallons of fuel per mile when its speed is v miles per hour, where k is a constant. At what speed should the truck travel so that it uses \(\frac{5}{12}\) gallon of fuel per mile?

(1) The value of k is \(\frac{1}{10800}\).
(2) When the truck travels at 30 miles per hour, it uses 1/6 gallon of fuel per mile.

_________________

"No pain, no gain

Current Student
User avatar
Joined: 06 Jan 2015
Posts: 59
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post 07 Feb 2016, 13:35
Consumption of fuel= 1/12+ kv^2


1. It gives you the actual value for the constant k, therefore you are able to find v from the original question. SUFFICIENT
2. It gives you: 1/6 = 1/12+ k30^2 , therefore you could find k and the use this to find v. SUFFICIENT

ANSWER D




BrainLab wrote:
A certain truck uses \(\frac{1}{12}+ kv^2\) gallons of fuel per mile when its speed is v miles per hour, where k is a constant. At what speed should the truck travel so that it uses \(\frac{5}{12}\) gallon of fuel per mile?

(1) The value of k is \(\frac{1}{10800}\).
(2) When the truck travels at 30 miles per hour, it uses 1/6 gallon of fuel per mile.

_________________

"No pain, no gain

Senior Manager
Senior Manager
avatar
G
Joined: 26 Dec 2015
Posts: 258
Location: United States (CA)
Concentration: Finance, Strategy
WE: Investment Banking (Venture Capital)
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post 16 Jan 2017, 15:07
1
You can solve this problem without doing any math.

Understand you're given 1 equation w/ 2 variables (k & v). To rephrase the Q, you need to find one variable to get the answer here.

(I) Gives you 1 variable (K). With this, you can find V. sufficient.
- Elim BCE

(II) Gives you equation: (1/6) = 1/12 + (30)^2(k). 30=V, so since they (indirectly) gave you (V), you can find (K). sufficient.
- Elim A

Ans: D
Intern
Intern
avatar
B
Joined: 18 Jan 2017
Posts: 36
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post 18 Jan 2017, 21:02
In fact, doing the actual calculation here will be very time consuming and un-necessary.
Intern
Intern
avatar
B
Joined: 05 Jan 2017
Posts: 23
Location: India
GMAT 1: 540 Q35 V29
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post 01 Mar 2017, 21:34
you have two unknowns in one equation - v and k.

a. gives you the value of one unknown - k - so you can calculate v - sufficient
b. gives you the value of v (can be computed with information given) - so you can derive the value of k - sufficient.
Intern
Intern
avatar
Joined: 27 Apr 2015
Posts: 8
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post 25 Sep 2017, 16:36
Statement 1 asks us to solve an equation with a squared variable, so why are there not two solutions? I thought equations to the second power always had two solutions. I answered B for this one.
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50715
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post 25 Sep 2017, 20:15
ThisandThat wrote:
Statement 1 asks us to solve an equation with a squared variable, so why are there not two solutions? I thought equations to the second power always had two solutions. I answered B for this one.


v is the speed of the truck. Can it be negative?
_________________

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

EMPOWERgmat Instructor
User avatar
V
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 12890
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post 14 Dec 2017, 15:29
Hi All,

We're told that a truck uses 1/12 + (K)(V^2) gallons of fuel per mile when its speed is V miles per hour and that K is a constant.
We're asked for the speed at which the truck travels so that it uses 5/12 gallon of fuel per mile.

To start, we can input the specific 'fuel usage' that the question asks us to deal with into the given equation:

5/12 = 1/12 + (K)(V^2)

Thus, to figure out the speed (V), we need to know the constant (K).

1) The value of K is 1/10,800

Fact 1 gives us the constant, we can figure out the value of V (and since we can't have a "negative speed", there's only one value for V^2 - the positive one).
Fact 1 is SUFFICIENT

2) When the truck travels at 30 miles per hour, it uses 1/6 gallon of fuel per mile.

We can plug this information into the equation, which gives us...

1/6 = 1/2 + (K)(30^2)

With this equation, we can then solve for K (which we could then plug back into the original question and solve for V).
Fact 2 is SUFFICIENT

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!*****

Target Test Prep Representative
User avatar
P
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 4170
Location: United States (CA)
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post 20 Dec 2017, 06:26
1
1
BrainLab wrote:
A certain truck uses \(\frac{1}{12}+ kv^2\) gallons of fuel per mile when its speed is v miles per hour, where k is a constant. At what speed should the truck travel so that it uses \(\frac{5}{12}\) gallon of fuel per mile?

(1) The value of k is \(\frac{1}{10800}\).
(2) When the truck travels at 30 miles per hour, it uses 1/6 gallon of fuel per mile.


We need to determine v when:

5/12 = 1/12 + kv^2

4/12 = kv^2

1/3 = kv^2

Statement One Alone:

The value of k is 1/10,800.

Thus, we have:

1/3 = (1/10,800)v^2

3600 = v^2

60 = v

Statement one alone is sufficient to answer the question.

Statement Two Alone:

When the truck travels at 30 miles per hour, it uses 1/6 gallon of fuel per mile.

Thus:

1/6 = 1/12 + k(30)^2

1/12 = 900k

1/10,800 = k

Since we have determined the value of k (the very same value of k in statement one), we can determine v. Statement two alone is sufficient to answer the question.

Answer: D
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Director
Director
User avatar
B
Status: No dream is too large, no dreamer is too small
Joined: 14 Jul 2010
Posts: 530
CAT Tests
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee  [#permalink]

Show Tags

New post 27 Jul 2018, 00:44
Top Contributor
BrainLab wrote:
A certain truck uses \(\frac{1}{12}+ kv^2\) gallons of fuel per mile when its speed is v miles per hour, where k is a constant. At what speed should the truck travel so that it uses \(\frac{5}{12}\) gallon of fuel per mile?

(1) The value of k is \(\frac{1}{10800}\).
(2) When the truck travels at 30 miles per hour, it uses 1/6 gallon of fuel per mile.


We have to work for:
(1/12) + kv^2 = 5/12

Option (1) K is given so we have to work for only v. Sufficient.
(2) we will get k from : (1/12) + k(30)^2 = 1/6, putting k in the original equation ((1/12) + kv^2 = 5/12) we will get v. sufficient

Ans. D.
_________________

Collections:-
PSof OG solved by GC members: http://gmatclub.com/forum/collection-ps-with-solution-from-gmatclub-110005.html
DS of OG solved by GC members: http://gmatclub.com/forum/collection-ds-with-solution-from-gmatclub-110004.html
100 GMAT PREP Quantitative collection http://gmatclub.com/forum/gmat-prep-problem-collections-114358.html
Collections of work/rate problems with solutions http://gmatclub.com/forum/collections-of-work-rate-problem-with-solutions-118919.html
Mixture problems in a file with best solutions: http://gmatclub.com/forum/mixture-problems-with-best-and-easy-solutions-all-together-124644.html

GMAT Club Bot
Re: A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee &nbs [#permalink] 27 Jul 2018, 00:44
Display posts from previous: Sort by

A certain truck uses 1/12 +kv^2 gallons of fuel per mile when its spee

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


cron
Copyright

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®.