BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

★★★★★5.0559 reviews
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

set 26 q 8

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 144
Joined: Fri Apr 13, 2007 2:25 am
by radhika1306 » Tue Sep 11, 2007 11:08 am
In the sequence 1, 2, 4, 8, 16, 32, … , each term after the first is twice the previous term. What is
the sum of the 16th, 17th, and 18th terms in the sequence?
A. 2^18
B. 3 (2^17)
C. 7 (2^16)
D. 3 (2^16)
E. 7 (2^15)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
Senior | Next Rank: 100 Posts
Posts: 71
Joined: Wed Aug 22, 2007 12:29 pmFollowed by: 1 member
Location: USA
Thanked: 12 times

Re: set 26 q 8

by wizardofwashington » Tue Sep 11, 2007 12:05 pm
radhika1306 wrote:In the sequence 1, 2, 4, 8, 16, 32, … , each term after the first is twice the previous term. What is
the sum of the 16th, 17th, and 18th terms in the sequence?
A. 2^18
B. 3 (2^17)
C. 7 (2^16)
D. 3 (2^16)
E. 7 (2^15)
IMO, the answer is E.
The sequence can be rewritten as 1, 2^1, 2^2, 2^3......2^15, 2^16,2^17 (the last three listed here are the 16th, 17th and 18th terms, which are of our interest).

The sum of the 16,17 & 18th terms = 2^15+2^16+2^17
= 2^15 (1+2+2^2)
= 2^15 (7)
Hence our answer should be E.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 321
Joined: Tue Aug 28, 2007 5:42 am
Thanked: 1 times

by kajcha » Tue Sep 11, 2007 12:09 pm
Agree E
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 144
Joined: Fri Apr 13, 2007 2:25 am

by radhika1306 » Thu Sep 13, 2007 9:29 am
correct thanks
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 645
Joined: Wed Sep 05, 2007 4:37 amFollowed by: 5 members
Location: India
Thanked: 34 times

by camitava » Thu Sep 13, 2007 8:25 pm
This is a GP (Geometric progression) and in GP to find out the nth number, the formula is -

Code: Select all

Tn = ar^(n - 1)

- where a = first term and r = common ratio.
So from this, you can get the 16, 17 and 18th number and sum them up and it will give the answer - E.
Correct me If I am wrong


Regards,

Amitava
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1