My Math Forum Arithmetic Progression help!

 Algebra Pre-Algebra and Basic Algebra Math Forum

 March 22nd, 2011, 06:28 AM #1 Member   Joined: Nov 2010 Posts: 39 Thanks: 0 Arithmetic Progression help! for hours i've been dealing with this problem and yet i cant really solve it. can you please help me with this one. PROBLEM The fifth term of an arithmetic sequence is 24 and the sum of the first 10 terms is 265. write the first three terms of the sequence. please help me. thank you in advance.
 March 22nd, 2011, 07:02 AM #2 Global Moderator     Joined: Oct 2008 From: London, Ontario, Canada - The Forest City Posts: 7,945 Thanks: 1136 Math Focus: Elementary mathematics and beyond Re: Arithmetic Progression help! (1): sum of an arithmetic series: $S_n\,=\,\frac{n}{2}$2a_1\,+\,(n\,-\,1)d$$ (2): nth term of an arithmetic progression: $a_n\,=\,a_1\,+\,(n\,-\,1)d$ From (1): $265\,=\,5$2a_1\,+\,9d$\,=\,10a_1\,+\,45d$ (3) From (2): $24\,=\,a_1\,+\,4d$ (4) Multiply (4) by 10: $240\,=\,10a_1\,+\,40d$ (5) Subtract (5) from (3): $25\,=\,5d,\,d\,=\,5$ First 3 terms: 4, 9, 14 . . .

 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post will.i.am1 Algebra 14 May 29th, 2013 06:27 AM Daksh Algebra 3 November 22nd, 2012 09:08 PM Algebra 2 April 5th, 2012 09:46 PM Trafford99 Algebra 7 February 28th, 2012 03:07 PM panky Algebra 4 November 17th, 2011 07:05 AM

 Contact - Home - Forums - Cryptocurrency Forum - Top