My Math Forum  

Go Back   My Math Forum > High School Math Forum > Algebra

Algebra Pre-Algebra and Basic Algebra Math Forum


Reply
 
LinkBack Thread Tools Display Modes
April 6th, 2015, 09:50 AM   #1
Member
 
Joined: Mar 2015
From: KY

Posts: 35
Thanks: 1

Geometric Sequence

Stuck on another one, I don't know what I'm doing wrong. I follow the formula and cannot get the right answer.

scsims is offline  
 
April 6th, 2015, 10:09 AM   #2
Member
 
Joined: Mar 2015
From: KY

Posts: 35
Thanks: 1

The answer I keep getting that I think is right is $34,440. But it says it's wrong.
scsims is offline  
April 6th, 2015, 10:10 AM   #3
Global Moderator
 
CRGreathouse's Avatar
 
Joined: Nov 2006
From: UTC -5

Posts: 16,046
Thanks: 938

Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms
What formula did you follow? What calculation did you make?
CRGreathouse is offline  
April 6th, 2015, 10:37 AM   #4
Member
 
Joined: Mar 2015
From: KY

Posts: 35
Thanks: 1

I used this one
scsims is offline  
April 6th, 2015, 12:28 PM   #5
Global Moderator
 
Joined: May 2007

Posts: 6,806
Thanks: 716

What values did you use for r, n, and a1?
mathman is offline  
April 6th, 2015, 02:02 PM   #6
Member
 
Joined: Mar 2015
From: KY

Posts: 35
Thanks: 1

I used:

a1=3075
r=1.025
n=10
scsims is offline  
April 7th, 2015, 05:17 AM   #7
Member
 
Joined: Mar 2015
From: KY

Posts: 35
Thanks: 1

Any more help?
scsims is offline  
April 7th, 2015, 06:52 AM   #8
Math Team
 
skeeter's Avatar
 
Joined: Jul 2011
From: Texas

Posts: 3,002
Thanks: 1587

did you try the hint that was given?

$\displaystyle 3000(1.025)^{10}+3000(1.025)^9+3000(1.025)^8+ ... +3000(1.025) =
$

$\displaystyle 3000\sum_{n=1}^{10} 1.025^n =$

$\displaystyle 3000 \cdot \frac{1.025(1-1.025^{10})}{1-1.025}$
skeeter is offline  
April 7th, 2015, 07:13 AM   #9
Member
 
Joined: Mar 2015
From: KY

Posts: 35
Thanks: 1

This was getting me the same answer that I was getting: \$34,440.

But when I worked it out individually for each year I got \$34,450 which is the right answer. Not sure where the issue is... rounding maybe?

Last edited by skipjack; April 7th, 2015 at 01:12 PM.
scsims is offline  
April 7th, 2015, 07:27 AM   #10
Math Team
 
skeeter's Avatar
 
Joined: Jul 2011
From: Texas

Posts: 3,002
Thanks: 1587

I got 34450.40 using the formula I posted ...
skeeter is offline  
Reply

  My Math Forum > High School Math Forum > Algebra

Tags
geometric, sequence



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
what if geometric sequence + geometric sequence frukoprof Computer Science 25 May 9th, 2013 07:35 PM
geometric sequence Vince604 Algebra 6 November 15th, 2012 08:39 PM
Sum of geometric sequence Eske939 Algebra 3 May 23rd, 2010 03:16 PM
geometric sequence Tafka Calculus 2 May 3rd, 2010 08:48 AM
what if geometric sequence + geometric sequence frukoprof Advanced Statistics 1 December 31st, 1969 04:00 PM





Copyright © 2019 My Math Forum. All rights reserved.