Remainder Problem

Expert replies

edvhou812: Master | Next Rank: 500 Posts; Posts: 143; Joined: Sat Nov 06, 2010 9:06 pmFollowed by: 1 member; Thanked: 10 times

by edvhou812 » Tue May 10, 2011 8:32 pm

If n divided by 7 has a remainder of 2, what is the remainder when 3 times n is divided by 7?

A: 1
B: 2
C: 3
D: 5
E: 6

My apologies if this has been addressed. I couldn't find it in the forum. Please post answer through the use of formulas/equations if possible.

Like this post

Source: Beat The GMAT — Problem Solving | Tue May 10, 2011 8:32 pm

manpsingh87: Master | Next Rank: 500 Posts; Posts: 436; Joined: Tue Feb 08, 2011 3:07 amFollowed by: 6 members; Thanked: 72 times

by manpsingh87 » Tue May 10, 2011 10:05 pm

edvhou812 wrote:If n divided by 7 has a remainder of 2, what is the remainder when 3 times n is divided by 7?

A: 1
B: 2
C: 3
D: 5
E: 6

My apologies if this has been addressed. I couldn't find it in the forum. Please post answer through the use of formulas/equations if possible.

as n leaves 2 as a remainder when divided by 7,, hence it can be represented as..!!
n=7k+2; where k=1,2,3,4,5,,,,;
3n= 21k+6;
3n/7 = 21k+6/7 which will leave 6 as remainder hence E

O Excellence... my search for you is on... you can be far.. but not beyond my reach!

Like this post

GMATGuruNY: GMAT Instructor; Posts: 15539; Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members; Location: New York, NY; Thanked: 13060 times; GMAT Score:790

by GMATGuruNY » Wed May 11, 2011 3:58 am

edvhou812 wrote:If n divided by 7 has a remainder of 2, what is the remainder when 3 times n is divided by 7?

A: 1
B: 2
C: 3
D: 5
E: 6

My apologies if this has been addressed. I couldn't find it in the forum. Please post answer through the use of formulas/equations if possible.

A formula will make the problem seem harder than it is.
Just plug in a value for n that, when divided by 7, leaves a remainder of 2:

Let n=9.
9/7 = 1 R2, so n=9 works.
3n = 3*9 = 27.
27/7 = 3 R6.

The correct answer is E.

Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

Like this post

GMAT/MBA Expert

Brent@GMATPrepNow: GMAT Instructor; Posts: 16207; Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members; Location: Vancouver, BC; Thanked: 5254 times; GMAT Score:770

by Brent@GMATPrepNow » Wed May 11, 2011 7:14 am

Mitch is right - it's often best to plug in numbers. Along that line, how do we find numbers that satisfy the given conditions?

There's a nice rule that goes like this:

If, when N is divided by D, the remainder is R, then the possible values of N include: R, R+D, R+2D, R+3D,. . .

Aside: the rule assumes that N, D and R are non-negative integers

I mention this because students often overlook the first option (R)

So, if we're told that n divided by 7 has a remainder of 2, then we know that the possible values of n include 2, 9, 16, 23, etc
2 is a possible value of n because if we divide 2 by 7 we get 0 with remainder 2

Cheers,
Brent

Brent Hanneson - Creator of GMATPrepNow.com

Like this post

edvhou812: Master | Next Rank: 500 Posts; Posts: 143; Joined: Sat Nov 06, 2010 9:06 pmFollowed by: 1 member; Thanked: 10 times

by edvhou812 » Wed May 11, 2011 6:54 pm

Thank you all for your answers. Each of them were helpful.

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

559 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review