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#1 2013-05-14 04:37:41

mom
Member
Registered: 2012-04-25
Posts: 94

finding the unpaid balance

I am just completely lost on this one. I am not coming up with anything close to what I should be.

A mortgage at 18% interest compounded monthly with a monthly payment of $500 has an unpaid balance of $5035.56 after 109 months. Find the unpaid balance after 110 months.

I used:
i=.015
n = 110
R = $500

P = [1-(1+i)^-n/i]*R

Please help.

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#2 2013-05-14 07:37:53

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 82,597

Re: finding the unpaid balance

Hi mom;

I am getting a principal of 27749.23 is that close?

If so then I am getting 4611.11 as the unpaid balance.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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#3 2013-05-14 08:59:57

mom
Member
Registered: 2012-04-25
Posts: 94

Re: finding the unpaid balance

Bobby,

I think so. 4611.09 was one of the options but how did you work it out?

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#4 2013-05-14 09:01:44

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 82,597

Re: finding the unpaid balance

I used a difference equation and then solved that. Fancy talk for I made a formula.

I only worked to 2 decimals when working to more I get 4611.09 as required.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

Online

#5 2013-05-14 09:13:59

mom
Member
Registered: 2012-04-25
Posts: 94

Re: finding the unpaid balance

thank you

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#6 2013-05-14 09:17:36

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 82,597

Re: finding the unpaid balance

Hi mom;

I can provide the formula if you would like. I do not know how useful it would be. perhaps if we work on it together we could make it more understandable. I know the math end but the money terms I am bad at.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

Online

#7 2013-05-14 09:19:05

mom
Member
Registered: 2012-04-25
Posts: 94

Re: finding the unpaid balance

the formula would be awsome

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#8 2013-05-14 09:24:46

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 82,597

Re: finding the unpaid balance

Hi;


numberpayments = 109

interest = .18 / 12

balance = 5035.56

Plug in and you will get p = 27749.22727276801

Now you have the original mortgage.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

Online

#9 2013-05-14 10:47:17

mom
Member
Registered: 2012-04-25
Posts: 94

Re: finding the unpaid balance

I guess it worked but I had to figure out the total cost as it was not provided so the balance was unknown. I had to work off of the payments for 3 years at once a month and the monthly interest.

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#10 2013-05-14 10:49:34

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 82,597

Re: finding the unpaid balance

Hi mom;

I am not exactly following you on that. I would go with the 4611.09.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

Online

#11 2013-05-15 03:18:17

mom
Member
Registered: 2012-04-25
Posts: 94

Re: finding the unpaid balance

Thank you for your help. I really do appreciate it.

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#12 2013-05-15 03:20:50

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 82,597

Re: finding the unpaid balance

Hi;

You are welcome.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

Online

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