GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

 It is currently 31 Mar 2020, 03:22

### 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

# A certain series of numbers has 15 terms in total. The first term of

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

### Hide Tags

e-GMAT Representative
Joined: 04 Jan 2015
Posts: 3337
A certain series of numbers has 15 terms in total. The first term of  [#permalink]

### Show Tags

15 May 2019, 01:01
00:00

Difficulty:

85% (hard)

Question Stats:

42% (02:23) correct 58% (02:21) wrong based on 79 sessions

### HideShow timer Statistics

A certain series of numbers has 15 terms in total. The first term of the sequence is -4. From the second term, every even numbered term is 3 more than the previous term, and every odd numbered term is 2 less than the previous term. How many terms are positive in the given series?

A. 7
B. 8
C. 9
D. 10
E. 11

_________________
GMAT Club Legend
Joined: 18 Aug 2017
Posts: 6063
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: A certain series of numbers has 15 terms in total. The first term of  [#permalink]

### Show Tags

15 May 2019, 09:12
Based on my understanding of the question ; solution as follows;

a1=-4
a2=-4+3;-1
a3=-1-2;-3
continue with same logic until a15
a4;0
a5;-2
a6;1
a7;-1
a8;2
a9;0
a10;3
a11;1
a12;4
a13;2
a14;5
a15;3

not to count 0 ; we get get 8 +ve integers
IMO B

EgmatQuantExpert wrote:
A certain series of numbers has 15 terms in total. The first term of the sequence is -4. From the second term, every even numbered term is 3 more than the previous term, and every odd numbered term is 2 less than the previous term. How many terms are positive in the given series?

A. 7
B. 8
C. 9
D. 10
E. 11

e-GMAT Representative
Joined: 04 Jan 2015
Posts: 3337
Re: A certain series of numbers has 15 terms in total. The first term of  [#permalink]

### Show Tags

20 May 2019, 03:03

Solution

Given:
In this question, we are given that
• A certain series of numbers has 15 terms in total.
• The first term of the sequence is -4.
• From the second term, every even numbered term is 3 more than the previous term, and every odd numbered term is 2 less than the previous term.

To find:
We need to determine
• The number of terms in the series, which are positive.

Approach and Working:
Let us determine the values of the individual terms, using the value of the first term.
• Term 1 = -4
• Term 2 = -4 + 3 = -1
• Term 3 = -1 – 2 = -3
• Term 4 = -3 + 3 = 0
• Term 5 = 0 – 2 = -2
• Term 6 = -2 + 3 = 1
• Term 7 = 1 – 2 = -1
• Term 8 = -1 + 3 = 2
• Term 9 = 2 – 2 = 0
• Term 10 = 0 + 3 = 3

Term 10 onwards all the terms will be positive.

As we can see, there are total 7 terms present in the series, which are either negative or 0.
• Therefore, the number of positive terms = 15 – 7 = 8

Hence, the correct answer is option B.

Answer: B

_________________
Re: A certain series of numbers has 15 terms in total. The first term of   [#permalink] 20 May 2019, 03:03
Display posts from previous: Sort by

# A certain series of numbers has 15 terms in total. The first term of

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

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