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
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:
In Episode 7 of our GMAT Ninja CR series, we are rounding up the oddballs, the misfits, and the format-benders: EXCEPT, Fill-In-The-Blanks, and other unusual Critical Reasoning question types. When you see a question that ends with a literal blank line
For most test takers, Data Insights is the most challenging section on the GMAT, with test takers scoring several points lower on average on DI than on Quant or Verbal and completing the section with less time to spare.
Register for the GMAT Club Virtual MBA Spotlight Fair – the world’s premier event for serious MBA candidates. This is your chance to hear directly from Admissions Directors at nearly every Top 30 MBA program..
For a Fibonacci sequence, from third term onwards each term is the sum previous 2 terms. If the difference in squares of seventh and sixth terms of this sequence is 517, what will be the tenth term of this sequence?
A. 147 B. 76 C. 123 D. can't be determined.
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
For a fibonacci sequence, from third term onwards each term is the sum previous 2 terms. If the difference in squares of seventh and sixth terms of this sequence is 517, What will be the tenth term of this sequence?
a) 147 b) 76 c) 123 d) can't be determined.
Show more
F7^2-F6^2=517
(F7-F6)*(F7+F6)=517
Prime factorization of 517=11*47. Hence: F7-F6=11 F7+F6=47
F7=29 and F6=18 F7+F6=F8=29+18=47 F7+F8=F9=29+47=76 F8+F9=F10=47+76=123
For a fibonacci sequence, from third term onwards each term is the sum previous 2 terms. If the difference in squares of seventh and sixth terms of this sequence is 517, What will be the tenth term of this sequence?
a) 147 b) 76 c) 123 d) can't be determined.
F7^2-F6^2=517
(F7-F6)*(F7+F6)=517
Prime factorization of 517=11*47. Hence: F7-F6=11 F7+F6=47
F7=29 and F6=18 F7+F6=F8=29+18=47 F7+F8=F9=29+47=76 F8+F9=F10=47+76=123
Answer: C.
P.S. This question is out of the scope of GMAT.
Show more
I think the answer should be 4. Cannot be determined as the even 1 * 517 could also be considered. In that case T6 and T7 would be 258 and 259, giving a different T10
Yes, Caligula is right that the answer should be 'cannot be determined', at least as the question is worded. They don't even tell us the numbers need to be integers, nor that they need to be positive. If you take the first solution above (where 18 and 29 are the sixth and seventh terms), and just make those numbers negative, you'll get another sequence that 'works', and -123 can be the tenth term. And if you allow non-integers in the sequence, there are infinitely many possibilities.
The question only has a unique answer if you know the terms must all be positive integers. Then the other factorization (1)(517) doesn't work, because that would force some of the earliest terms in the sequence to be negative. Either way, it's not a realistic GMAT question at all, so test takers shouldn't worry about it.
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.