Events & Promotions
|
|
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Nov 1912:30 PM EST
-01:30 PM EST
Learn how Keshav, a Chartered Accountant, scored an impressive 705 on GMAT in just 30 days with GMATWhiz's expert guidance. In this video, he shares preparation tips and strategies that worked for him, including the mock, time management, and more
Nov 2001:30 PM EST
-02:30 PM IST
Learn how Kamakshi achieved a GMAT 675 with an impressive 96th %ile in Data Insights. Discover the unique methods and exam strategies that helped her excel in DI along with other sections for a balanced and high score.
Nov 2211:00 AM IST
-01:00 PM IST
Do RC/MSR passages scare you? e-GMAT is conducting a masterclass to help you learn – Learn effective reading strategies Tackle difficult RC & MSR with confidence Excel in timed test environment- Nov 23
11:00 AM IST
-01:00 PM IST
Attend this free GMAT Algebra Webinar and learn how to master the most challenging Inequalities and Absolute Value problems with ease. 
Nov 2407:00 PM PST
-08:00 PM PST
Full-length FE mock with insightful analytics, weakness diagnosis, and video explanations!
Nov 2510:00 AM EST
-11:00 AM EST
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors.
26 Jul 2023, 08:00
Kudos
Bookmarks
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
95%
(hard)
Question Stats:
44% (02:25) correct
56%
(02:37)
wrong
based on 561
sessions
History
Date
Time
Result
Not Attempted Yet
The infinite sequence A is such that \(a_1=3\) and \(a_{n} = a_{n-1} + 3*10^{n-1}\), for all n > 1. If each term in the product \(x_1*x_2*x_3*...*x_k\) is taken from the infinite sequence A, repetitions allowed, and the product equals 173,446,418,443,770,747, which of the following could be equal to k?
A. 16
B. 17
C. 18
D. 19
E. 20
A. 16
B. 17
C. 18
D. 19
E. 20
|
Experience GMAT Club Test Questions
Yes, you've landed on a GMAT Club Tests question
Craving more? Unlock our full suite of GMAT Club Tests here
Want to experience more? Get a taste of our tests with our free trial today
Rise to the challenge with GMAT Club Tests. Happy practicing!
26 Jul 2023, 08:37
Kudos
Bookmarks
given that
a1= 3
a2 will be 33
a3 = 333
a4=3333
product of values is 173,446,418,443,770,747,
last digit is 7
cyclicity of 3 is (4)
3^1 =3
3^2=9
3^3=7
3^4=1
value of k must be 19 to get the product value ending with digit 7
option D is correct
a1= 3
a2 will be 33
a3 = 333
a4=3333
product of values is 173,446,418,443,770,747,
last digit is 7
cyclicity of 3 is (4)
3^1 =3
3^2=9
3^3=7
3^4=1
value of k must be 19 to get the product value ending with digit 7
option D is correct
Bunuel
General Discussion
26 Jul 2023, 08:42
Kudos
Bookmarks
Let's calculate the first few terms of the sequence A to get a better understanding:
a1 = 3
a2 = a1 + 3*10^1 = 3 + 30 = 33
a3 = a2 + 3*10^2 = 33 + 300 = 333
a4 = a3 + 3*10^3 = 333 + 3000 = 3333
and so on...
We can see that each term in the sequence A is a string of 3's, the length of which is equal to the term's position in the sequence.
Now, we are given that the product of some terms from the sequence A equals 173,446,418,443,770,747. We are asked to find the number of terms in this product, which is represented by k.
Since unit digit is 7 and we know unit digit in power series of 3 is : 3,9,7,1
To have unit digit as 7, we need k of form 4p+3
So 19 is the correct answer
Answer is D
a1 = 3
a2 = a1 + 3*10^1 = 3 + 30 = 33
a3 = a2 + 3*10^2 = 33 + 300 = 333
a4 = a3 + 3*10^3 = 333 + 3000 = 3333
and so on...
We can see that each term in the sequence A is a string of 3's, the length of which is equal to the term's position in the sequence.
Now, we are given that the product of some terms from the sequence A equals 173,446,418,443,770,747. We are asked to find the number of terms in this product, which is represented by k.
Since unit digit is 7 and we know unit digit in power series of 3 is : 3,9,7,1
To have unit digit as 7, we need k of form 4p+3
So 19 is the correct answer
Answer is D
