My Math Forum rest

 Algebra Pre-Algebra and Basic Algebra Math Forum

 April 12th, 2014, 12:10 PM #1 Senior Member   Joined: Nov 2013 Posts: 434 Thanks: 8 rest if we divide n by 7 rest =3 if we divide 5n+4 by 7 what the rest
 April 12th, 2014, 01:28 PM #2 Global Moderator   Joined: May 2007 Posts: 6,807 Thanks: 717 5x3 + 4 = 19, mod 7 = 5.
April 12th, 2014, 05:37 PM   #3
Math Team

Joined: Dec 2006
From: Lexington, MA

Posts: 3,267
Thanks: 408

Hello, mared!

Quote:
 If we divide $\displaystyle n$ by 7, the remainder is 3. What is the remainder if we divide $\displaystyle 5n+4$ by 7 ?

We are told that: $\displaystyle \;n \:=\:7a+3$ for some integer $\displaystyle a.$

Then $\displaystyle \:5n+4 \;=\;5(7a+3)+4 \;=\;35a + 15 + 4 \;=\;35a + 19$

Hence: $\displaystyle \;\frac{5n+4}{7} \;=\; \frac{35a+19}{7} \;=\;5a + 2 + \frac{5}{7}$

Therefore, the remainder is $\displaystyle 5.$

 Tags rest

 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post mathkid Physics 9 February 1st, 2013 06:03 PM poisonpoison Algebra 0 October 15th, 2011 01:00 PM Rem700PSS Algebra 1 January 31st, 2010 05:05 PM mathkid Algebra 0 December 31st, 1969 04:00 PM

 Contact - Home - Forums - Cryptocurrency Forum - Top