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:
Kick off your 2019 GMAT prep with a free 7-day boot camp that includes free online lessons, webinars, and a full GMAT course access. Limited for the first 99 registrants! Feb. 21st until the 27th.
Re: What is the remainder when 7^9 - 4 is divided by 7?
[#permalink]
Show Tags
14 Apr 2017, 05:27
2
Top Contributor
amathews wrote:
What is the remainder when 7^9 - 4 is divided by 7?
A)1 B)2 C)3 D)4 E)5
If we take 7^9 - 4 and zero to it, the value doesn't change. We're going to add zero by subtracting 3 and adding 3 at the same time. So, 7^9 - 4 = 7^9 - 4 - 3 + 3 = 7^9 - 7+ 3 = 7(7^8 - 1)+ 3 = 7(some integer)+ 3
As we can see, our initial number can be rewritten as 3 more thansome multiple of 7. So, if we divide that number by 7, the remainder will be 3
Re: What is the remainder when 7^9 - 4 is divided by 7?
[#permalink]
Show Tags
14 Apr 2017, 07:35
Chemerical71 wrote:
Bunuel wrote:
amathews wrote:
What is the remainder when 7^9 - 4 is divided by 7?
A)1 B)2 C)3 D)4 E)5
7^9 - 4 = {a multiple of 7} - 4, so it's 4 less than a multiple of 7 (3, 10, 17, ...), so the remainder is 3.
Answer: C.
Hello Bunnel. When it is 7^8 -4 then what would be remainder. Thanks in advance.
It seems that you did not understand the explanation. The remainder of 7^n - 4 divided by 7 where n is a positive integer is always 3.
_________________
Re: What is the remainder when 7^9 - 4 is divided by 7?
[#permalink]
Show Tags
19 Jan 2019, 09:28
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.
_________________
close
71% (00:55) correct 
