January 26, 2019 January 26, 2019 07:00 AM PST 09:00 AM PST Attend this webinar to learn how to leverage Meaning and Logic to solve the most challenging Sentence Correction Questions. January 27, 2019 January 27, 2019 07:00 AM PST 09:00 AM PST Attend this webinar to learn a structured approach to solve 700+ Number Properties question in less than 2 minutes.
Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 52431

If a, b, c, and d are consecutive integers and a < b < c < d, what is
[#permalink]
Show Tags
22 Jan 2018, 00:54
Question Stats:
79% (01:27) correct 21% (01:46) wrong based on 96 sessions
HideShow timer Statistics
If a, b, c, and d are consecutive integers and a < b < c < d, what is the average (arithmetic mean) of a, b, c, and d in terms of d? (A) d – 5/2 (B) d – 2 (C) d – 3/2 (D) d + 3/2 (E) (4d – 6)/7
Official Answer and Stats are available only to registered users. Register/ Login.
_________________
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? Extrahard Quant Tests with Brilliant Analytics



Manager
Joined: 16 Jan 2018
Posts: 91
Location: New Zealand

Re: If a, b, c, and d are consecutive integers and a < b < c < d, what is
[#permalink]
Show Tags
22 Jan 2018, 01:02
Since they are consecutive integers, therefore a=d3; b=d2; c=d1; Taking average, (d3+d2+d1+d)/4 = (4d6)/4 = d3/2 Option C. Sent from my ONE E1003 using GMAT Club Forum mobile app



Senior DS Moderator
Joined: 27 Oct 2017
Posts: 1199
Location: India
Concentration: International Business, General Management
GPA: 3.64
WE: Business Development (Energy and Utilities)

Re: If a, b, c, and d are consecutive integers and a < b < c < d, what is
[#permalink]
Show Tags
22 Jan 2018, 06:05
Please see my approach Bunuel wrote: If a, b, c, and d are consecutive integers and a < b < c < d, what is the average (arithmetic mean) of a, b, c, and d in terms of d?
(A) d – 5/2
(B) d – 2
(C) d – 3/2
(D) d + 3/2
(E) (4d – 6)/7
Attachments
20180122 at 193216.jpg [ 16.79 KiB  Viewed 865 times ]
_________________
Win GMAT CLUB Test Weekly Quant Quiz Contest Weekly Quant Quiz Questions Direct Download SC: Confusable words All you need for Quant, GMAT PS Question Directory,GMAT DS Question Directory Error log/Key Concepts Combination Concept: Division into groups Question of the Day (QOTD) Free GMAT CATS



Intern
Joined: 27 Jan 2017
Posts: 23

Re: If a, b, c, and d are consecutive integers and a < b < c < d, what is
[#permalink]
Show Tags
22 Jan 2018, 07:11
Bunuel wrote: If a, b, c, and d are consecutive integers and a < b < c < d, what is the average (arithmetic mean) of a, b, c, and d in terms of d?
(A) d – 5/2
(B) d – 2
(C) d – 3/2
(D) d + 3/2
(E) (4d – 6)/7 Answer: C Since consecutive integers, thus a = d3 b = d2 c = d1 Mean = (a + b +c + d) / 4 Substituting a, b and c in above we get option C



Director
Joined: 31 Jul 2017
Posts: 518
Location: Malaysia
GPA: 3.95
WE: Consulting (Energy and Utilities)

Re: If a, b, c, and d are consecutive integers and a < b < c < d, what is
[#permalink]
Show Tags
22 Jan 2018, 07:36
Bunuel wrote: If a, b, c, and d are consecutive integers and a < b < c < d, what is the average (arithmetic mean) of a, b, c, and d in terms of d?
(A) d – 5/2
(B) d – 2
(C) d – 3/2
(D) d + 3/2
(E) (4d – 6)/7 As the numbers are consecutive, let the numbers be c2, c1,c , c+1 A.M = (4c2)/4 = c (1/2).. Also, as d = c+1 from above equation, c = d  1 So, AM = d (3/2)
_________________
If my Post helps you in Gaining Knowledge, Help me with KUDOS.. !!



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 8810
Location: Pune, India

Re: If a, b, c, and d are consecutive integers and a < b < c < d, what is
[#permalink]
Show Tags
22 Jan 2018, 22:21
The moment I see consecutive integers and a < b< c< d, I think of 1,2 ,3 ,4. Average is 2.5 which is 4  1.5 i.e. d  3/2 Answer (C)
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >



Manager
Joined: 03 Oct 2016
Posts: 126

Re: If a, b, c, and d are consecutive integers and a < b < c < d, what is
[#permalink]
Show Tags
22 Jan 2018, 22:29
1. Av= \(\frac{(A+D)}{2}\) (as it is consecutive evenly spaced numbers) 2. Range = DA=3 (as it is consecutive numbers with increment of 1) 3. Substitute A= D3 in 1. Av=\(\frac{(D3+D)}{2}\) >Av=\(\frac{(2D3)}{2}\) 4. After dividing by 2 it becomes Av=D\(\frac{3}{2}\). Answer (C)
_________________
NonAllergic To Kudos



Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2830

Re: If a, b, c, and d are consecutive integers and a < b < c < d, what is
[#permalink]
Show Tags
23 Jan 2018, 07:53
Bunuel wrote: If a, b, c, and d are consecutive integers and a < b < c < d, what is the average (arithmetic mean) of a, b, c, and d in terms of d?
(A) d – 5/2
(B) d – 2
(C) d – 3/2
(D) d + 3/2
(E) (4d – 6)/7 We can label our consecutive integers as: d c = d  1 b = d  2 a = d  3 Using the formula for the arithmetic average (mean), we have: average = (d + d  1 + d  2 + d  3)/4 = (4d  6)/4 = 4d/4  6/4 = d  3/2 Answer: C
_________________
Jeffery Miller
Head of GMAT Instruction
GMAT Quant SelfStudy Course
500+ lessons 3000+ practice problems 800+ HD solutions




Re: If a, b, c, and d are consecutive integers and a < b < c < d, what is &nbs
[#permalink]
23 Jan 2018, 07:53






