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.
Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:
The sequence of four numbers a1, a2 , a3 and a4 is such that
[#permalink]
Show Tags
18 May 2013, 01:25
2
10
00:00
A
B
C
D
E
Difficulty:
15% (low)
Question Stats:
76% (01:17) correct 24% (01:38) wrong based on 364 sessions
HideShow timer Statistics
The sequence of four numbers \(a_1\), \(a_2\) , \(a_3\) and \(a_4\) is such that each number after the first is \(a_1-1\) greater than preceding number . What is the value of \(a_1\)?
Re: The sequence of four numbers a1, a2 , a3 and a4 is such that
[#permalink]
Show Tags
18 May 2013, 01:37
3
The sequence of four numbers \(a_1\), \(a_2\) , \(a_3\) and \(a_4\) is such that each number after the first is \(a_1-1\) greater than preceding number . What is the value of \(a_1\)?
Re: The sequence of four numbers a1, a2 , a3 and a4 is such that
[#permalink]
Show Tags
18 May 2013, 05:10
pritishmohan wrote:
The sequence of four numbers \(a_1\), \(a_2\) , \(a_3\) and \(a_4\) is such that each number after the first is \(a_1-1\) greater than preceding number . What is the value of \(a_1\)?
1. \(a_2=15\)
2. \(a_4 = 29\)
given:- a2 - a1 = a1 - 1 => a2 = 2a1 - 1
similarly we can get a3 = 3a1 - 2 and a4 = 4a1 - 3.
AD/BCE
statement 1:- a2 = 15 => 2a1 - 1 = 15.So we can get the value of a1. A alone is sufficient BCE out.
statement2:- a4 = 29 => 4a1-3 = 29 .So we can get the value of a1. B alone is sufficient.
Answer is D
_________________
"Kudos" will help me a lot!!!!!!Please donate some!!!
Completed Official Quant Review OG - Quant
In Progress Official Verbal Review OG 13th ed MGMAT IR AWA Structure
Yet to do 100 700+ SC questions MR Verbal MR Quant
Re: The sequence of four numbers a1, a2 , a3 and a4 is such that
[#permalink]
Show Tags
19 May 2013, 04:35
pritishmohan wrote:
The sequence of four numbers \(a_1\), \(a_2\) , \(a_3\) and \(a_4\) is such that each number after the first is \(a_1-1\) greater than preceding number . What is the value of \(a_1\)?
1. \(a_2=15\)
2. \(a_4 = 29\)
From the given information, we know that \(a_n = a_{n-1} + (a_1 - 1) = na_1 - (n - 1)\)
Re: The sequence of four numbers a1, a2 , a3 and a4 is such that
[#permalink]
Show Tags
19 May 2013, 04:40
3
pritishmohan wrote:
The sequence of four numbers \(a_1\), \(a_2\) , \(a_3\) and \(a_4\) is such that each number after the first is \(a_1-1\) greater than preceding number . What is the value of \(a_1\)?
Re: The sequence of four numbers a1, a2 , a3 and a4 is such that
[#permalink]
Show Tags
30 Oct 2014, 02:52
2
1
alexa wrote:
Bunuel please solve this question, I don't understand the solution for statement #2.
Thank you!
The sequence of four numbers \(a_1\), \(a_2\) , \(a_3\) and \(a_4\) is such that each number after the first is \(a_1-1\) greater than preceding number . What is the value of \(a_1\)?
Each number after the first is \(a_1-1\) greater than preceding number means that: \(a_2=a_1+(a_1-1)=2a_1-1\) \(a_3=a_2+(a_1-1)=3a_1-2\) \(a_4=a_3+(a_1-1)=4a_1-3\)
(1) \(a_2=15\). We can find \(a_1\). Sufficient.
(2) \(a_4 = 29\). We can find \(a_1\). Sufficient.
The sequence of four numbers a1, a2 , a3 and a4 is such that
[#permalink]
Show Tags
12 Nov 2015, 04:25
pritishmohan wrote:
The sequence of four numbers \(a_1\), \(a_2\) , \(a_3\) and \(a_4\) is such that each number after the first is \(a_1-1\) greater than preceding number . What is the value of \(a_1\)?
(1) \(a_2=15\)
(2) \(a_4 = 29\)
Given: \(a_1\), \(a_2\) , \(a_3\) and \(a_4\) and \(a_2\) = \(a_1\) + \(a_1-1\) - (i) \(a_3\) = \(a_1\) + 2\(a_1-1\) - (ii) \(a_4\) = \(a_1\) + 3\(a_1-1\) - (iii)
Required: \(a_1\) = ?
Statement 1: \(a_2=15\) Using (i) we can find the value of \(a_1\) SUFFICIENT
Statement 2: \(a_4 = 29\) Using (iii), we can find the value of \(a_1\) SUFFICIENT
Hence Option D
Note: You do not need to solve for the values of \(a_1\). This can save precious time on the test.
close
76% (01:17) correct 
