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

 It is currently 19 Oct 2019, 13:41 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

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.  Given the sequence above, what is the sum of the 10th and the 20th

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

Hide Tags

Math Expert V
Joined: 02 Sep 2009
Posts: 58445
Given the sequence above, what is the sum of the 10th and the 20th  [#permalink]

Show Tags 00:00

Difficulty:   5% (low)

Question Stats: 87% (01:38) correct 13% (01:45) wrong based on 118 sessions

HideShow timer Statistics

8, 19, 30, 41, 52, ….
Given the sequence above, what is the sum of the 10th and the 20th terms?

A. 324
B. 335
C. 346
D. 357
E. 368

Kudos for a correct solution.

_________________
CEO  S
Joined: 20 Mar 2014
Posts: 2597
Concentration: Finance, Strategy
Schools: Kellogg '18 (M)
GMAT 1: 750 Q49 V44 GPA: 3.7
WE: Engineering (Aerospace and Defense)
Given the sequence above, what is the sum of the 10th and the 20th  [#permalink]

Show Tags

1
Bunuel wrote:
8, 19, 30, 41, 52, ….
Given the sequence above, what is the sum of the 10th and the 20th terms?

A. 324
B. 335
C. 346
D. 357
E. 368

Kudos for a correct solution.

GIven sequence = 8,19,30,41,52....

Thus $$S_n = S_{n-1} + 11$$

$$S_{10} = S_1+(10-1)*11 = 8+9*11$$
$$S_{20} = S_1+(20-1)*11= 8+19*11$$

Thus the sum = 8+9*11+ 8+19*11 = 16+11(20+8) = 16+220+88 = 220+104 = 324. A is the correct answer.
Senior Manager  B
Joined: 28 Jun 2015
Posts: 283
Concentration: Finance
GPA: 3.5
Re: Given the sequence above, what is the sum of the 10th and the 20th  [#permalink]

Show Tags

1
8, 19, 30, 41, 52, ...

a = 8, d = 11.

10th term = a+9d = 8+9*11 = 107
20th term = a+21d = 8+19*11 = 217

sum = 107+217 = 324. Ans (A).
_________________
I used to think the brain was the most important organ. Then I thought, look what’s telling me that.
CEO  D
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 2978
Location: India
GMAT: INSIGHT
Schools: Darden '21
WE: Education (Education)
Re: Given the sequence above, what is the sum of the 10th and the 20th  [#permalink]

Show Tags

1
Bunuel wrote:
8, 19, 30, 41, 52, ….
Given the sequence above, what is the sum of the 10th and the 20th terms?

A. 324
B. 335
C. 346
D. 357
E. 368

Kudos for a correct solution.

This is an Arithmatic progression with First term 8 and Common Difference = 19-8 = 30-19 = 11

10th Term = First term + 9*Common Difference = 8+9*11 = 107

20th Term = First term + 19*Common Difference = 8+19*11 = 217

Difference = 217 + 107 = 324

_________________
Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

ACCESS FREE GMAT TESTS HERE:22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION
Director  P
Joined: 21 May 2013
Posts: 636
Re: Given the sequence above, what is the sum of the 10th and the 20th  [#permalink]

Show Tags

1
Bunuel wrote:
8, 19, 30, 41, 52, ….
Given the sequence above, what is the sum of the 10th and the 20th terms?

A. 324
B. 335
C. 346
D. 357
E. 368

Kudos for a correct solution.

The terms are in A.P
a=8, d=11
a10=a+9d=8+9(11)=107
And, a20=a+19d=9+19(11)=217
Therefore, a10+a20=107+217=324
Manager  Joined: 20 Jul 2011
Posts: 79
GMAT 1: 660 Q49 V31 Given the sequence above, what is the sum of the 10th and the 20th  [#permalink]

Show Tags

1
Bunuel wrote:
8, 19, 30, 41, 52, ….
Given the sequence above, what is the sum of the 10th and the 20th terms?

A. 324
B. 335
C. 346
D. 357
E. 368

Kudos for a correct solution.

First term a =8
Difference btw two consecutive terms = 11

Formula to calculate nth term when the seq is A.P is = a + (n-1)* d

10th term = 8 + (10-1) * 11 = 107
20th term = 8 + (20-1) * 11 = 217

Sum = 107+217 = 324

Option A
Manager  Status: GMAT Date: 10/08/15
Joined: 17 Jul 2014
Posts: 84
Location: United States (MA)
Concentration: Human Resources, Strategy
GMAT 1: 640 Q48 V35 GPA: 3.5
WE: Human Resources (Consumer Products)
Re: Given the sequence above, what is the sum of the 10th and the 20th  [#permalink]

Show Tags

1
The series has numbers spaced out by 11. So the equation can be written as 8+ 11(n-1).

The 10th number will be - 8+11(9) = 107
20th number - 8+11(19) = 217

Sum is 324, hence answer is A

Bunuel wrote:
8, 19, 30, 41, 52, ….
Given the sequence above, what is the sum of the 10th and the 20th terms?

A. 324
B. 335
C. 346
D. 357
E. 368

Kudos for a correct solution.

_________________
Thanks,
aimtoteach

~~~~~~~~~~~~~~~~~

Please give Kudos if you find this post useful.
Intern  Joined: 11 Dec 2013
Posts: 7
Re: Given the sequence above, what is the sum of the 10th and the 20th  [#permalink]

Show Tags

1
This is a case of AP with following :
first term=8, difference=11.

To find the 10th term, use the following formula:
nth term==a+(n-1)*d, where a==first term, n==number of terms, d==difference

10th term = 8 + (10-1) * 11 ==107
20th term = 8 + (20-1) * 11 ==217

Sum of 10th and 20th term = 107 + 217 == 324. A is correct answer

Regards
Naresh Mittal
Math Expert V
Joined: 02 Sep 2009
Posts: 58445
Re: Given the sequence above, what is the sum of the 10th and the 20th  [#permalink]

Show Tags

Bunuel wrote:
8, 19, 30, 41, 52, ….
Given the sequence above, what is the sum of the 10th and the 20th terms?

A. 324
B. 335
C. 346
D. 357
E. 368

Kudos for a correct solution.

800score Official Solution:

First, we need to derive a formula so that we do not need to write out the first 20 terms.
The first term is 8 = 11 – 3. The second term is 19 = 22 – 3, the third term is 30 = 3 × 11 – 3, the fourth term is 41 = 4 × 11 – 3, etc.
Thus, 11n – 3 describes the values in the sequence where n is the number of the term.
The 10th term is 10 × 11 – 3 = 107.
The 20th term is 20 × 11 – 3 = 220 – 3 = 217.
The sum of these two values is 324.

The correct answer is choice (A).
_________________
Non-Human User Joined: 09 Sep 2013
Posts: 13275
Re: Given the sequence above, what is the sum of the 10th and the 20th  [#permalink]

Show Tags

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________ Re: Given the sequence above, what is the sum of the 10th and the 20th   [#permalink] 16 Dec 2018, 18:58
Display posts from previous: Sort by

Given the sequence above, what is the sum of the 10th and the 20th

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne  