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

 It is currently 15 Dec 2019, 02:49

### 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

# What is the difference between the sixth and the fifth terms

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

### Hide Tags

Manager
Joined: 02 Dec 2012
Posts: 173
What is the difference between the sixth and the fifth terms  [#permalink]

### Show Tags

20 Dec 2012, 09:02
2
15
00:00

Difficulty:

5% (low)

Question Stats:

84% (01:25) correct 16% (01:30) wrong based on 1560 sessions

### HideShow timer Statistics

What is the difference between the sixth and the fifth terms of the sequence 2, 4, 7, ... whose nth term is n + 2^(n - 1)?

(A) 2
(B) 3
(C) 6
(D) 16
(E) 17
Math Expert
Joined: 02 Sep 2009
Posts: 59726
Re: What is the difference between the sixth and the fifth terms  [#permalink]

### Show Tags

20 Dec 2012, 09:04
3
1
Walkabout wrote:
What is the difference between the sixth and the fifth terms of the sequence 2, 4, 7, ... whose nth term is n + 2^(n - 1)?

(A) 2
(B) 3
(C) 6
(D) 16
(E) 17

Given that $$a_n=n+2^{n-1}$$, thus:

$$a_6=6+2^{6-1}=38$$;
$$a_5=5+2^{5-1}=21$$;

The difference is 38-21=17.

Answer: E.
_________________
Manager
Joined: 22 Nov 2016
Posts: 205
Location: United States (CA)
Concentration: Leadership, Strategy
Schools: Haas EWMBA '22
GMAT 1: 640 Q43 V35
GPA: 3.4
Re: What is the difference between the sixth and the fifth terms  [#permalink]

### Show Tags

29 Jun 2017, 19:28
1
Notice that 2 raised to any positive number will aways be even.

Hence the sixth term will be even+even = even
The fifth term will be odd+even = odd

The only two answers that are odd are B and E. I would say that looking at the sequence we can say that the gap is expanding, hence answer is E
Manager
Joined: 10 Aug 2009
Posts: 68
Location: United States (VA)
Concentration: Entrepreneurship, Strategy
Schools: Darden '17 (M\$)
WE: Business Development (Other)
Re: What is the difference between the sixth and the fifth terms  [#permalink]

### Show Tags

25 Nov 2014, 14:02
Bunuel wrote:
Walkabout wrote:
What is the difference between the sixth and the fifth terms of the sequence 2, 4, 7, ... whose nth term is n + 2^(n - 1)?

(A) 2
(B) 3
(C) 6
(D) 16
(E) 17

Given that $$a_n=n+2^{n-1}$$, thus:

$$a_6=6+2^{6-1}=38$$;
$$a_5=5+2^{5-1}=21$$;

The difference is 38-21=17.

Answer: E.

Just one question, why do they mention 2, 4, 7. Is that to throw a test-taker off?
_________________
"Popular opinion is the greatest lie in the world"-Thomas Carlyle
Math Expert
Joined: 02 Sep 2009
Posts: 59726
Re: What is the difference between the sixth and the fifth terms  [#permalink]

### Show Tags

26 Nov 2014, 05:10
Bigred2008 wrote:
Bunuel wrote:
Walkabout wrote:
What is the difference between the sixth and the fifth terms of the sequence 2, 4, 7, ... whose nth term is n + 2^(n - 1)?

(A) 2
(B) 3
(C) 6
(D) 16
(E) 17

Given that $$a_n=n+2^{n-1}$$, thus:

$$a_6=6+2^{6-1}=38$$;
$$a_5=5+2^{5-1}=21$$;

The difference is 38-21=17.

Answer: E.

Just one question, why do they mention 2, 4, 7. Is that to throw a test-taker off?

2, 4, and 7, are the first, second and the third terms of the sequence whose nth term is n + 2^(n - 1). For n = 1, n + 2^(n - 1) = 1 + 2^0 = 2, for n = 2, n + 2^(n - 1) = 2 + 2^1 = 4, and for n = 3, n + 2^(n - 1) = 3 + 2^2 = 7. So, those numbers are given simply as an example.
_________________
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8701
Location: United States (CA)
Re: What is the difference between the sixth and the fifth terms  [#permalink]

### Show Tags

13 Jul 2016, 07:30
Walkabout wrote:
What is the difference between the sixth and the fifth terms of the sequence 2, 4, 7, ... whose nth term is n + 2^(n - 1)?

(A) 2
(B) 3
(C) 6
(D) 16
(E) 17

For the sixth term, we need to substitute 6 for n, and for the fifth term, we need to substitute 5 for n. Then we'll find the difference between the two terms.

Let’s first plug 6 in for n.

6 + 2^(6-1)

6 + 2^5

6 + 32 = 38

Next let’s plug 5 in for n.

5 + 2^(5-1)

5 + 2^4

5 + 16 = 21

Thus, the difference between the 6th and 5th term of the sequence is 38 – 21 = 17.

Answer is E.
_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Intern
Joined: 24 Sep 2016
Posts: 33
Location: United States (CT)
Concentration: Finance, International Business
GPA: 3.81
WE: Analyst (Venture Capital)
Re: What is the difference between the sixth and the fifth terms  [#permalink]

### Show Tags

31 Jan 2017, 17:37
Plug in 6 and 5 for the sixth and fifth sequence respectively.....

Sixth sequence = 6 + 2^(6-1) = 38

Fifth sequence = 5 + 2^(5-1) = 21

38-21
=
17
Senior Manager
Joined: 12 Dec 2015
Posts: 447
Re: What is the difference between the sixth and the fifth terms  [#permalink]

### Show Tags

22 Oct 2019, 07:27
What is the difference between the sixth and the fifth terms of the sequence 2, 4, 7, ... whose nth term is n + 2^(n - 1)?

(A) 2
(B) 3
(C) 6
(D) 16
(E) 17--> correct

Analysis: t6-t5 = 6 + 2^5 - 5 -2^4=1+2^4=17
Intern
Joined: 28 Jan 2019
Posts: 37
Re: What is the difference between the sixth and the fifth terms  [#permalink]

### Show Tags

26 Nov 2019, 09:23
n6 = 6+2^5
n5 = 5+2^4

n6-n5= 6+2^5-(5+2^4)
=1+2^5-2^4
=1+2^4(2-1)
=1+16(1)
=17
Re: What is the difference between the sixth and the fifth terms   [#permalink] 26 Nov 2019, 09:23
Display posts from previous: Sort by

# What is the difference between the sixth and the fifth terms

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

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