
Algebra PreAlgebra and Basic Algebra Math Forum 
 LinkBack  Thread Tools  Display Modes 
January 6th, 2019, 05:46 AM  #1 
Member Joined: Aug 2018 From: Nigeria Posts: 73 Thanks: 2  Sequence&Series
Given the exponential sequence 3, 9/2, 27/4, ..., find the number of terms for its sum to be greater than 368.
Last edited by skipjack; January 6th, 2019 at 01:09 PM. 
January 6th, 2019, 01:06 PM  #2 
Global Moderator Joined: Dec 2006 Posts: 20,757 Thanks: 2138 
Use a calculator to find the total of, say, the first 12 terms. What do you get? The first 9 terms total $224 \frac{169}{256}$. 
January 6th, 2019, 07:07 PM  #3 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 14,597 Thanks: 1038 
a = 3 (1st term), m = 3/2 (common multiplier) Assume sum = 368 a(m^n  1) / (m  1) = 368 n = ~10.192 So 11. 

Tags 
sequence, sequenceandseries 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
sequence and series  harshjnr  Calculus  1  March 8th, 2016 08:40 AM 
Sequence and series  naman  Algebra  3  March 5th, 2013 04:37 AM 
Is this a sequence? Series?  suomik1988  Algebra  5  December 8th, 2010 07:38 AM 
Series and Sequence help  danield3  Algebra  1  May 5th, 2010 07:15 PM 
Is this a sequence? Series?  suomik1988  Calculus  5  December 31st, 1969 04:00 PM 