Is this right math?

[Kruno]

I know the code and all is right.

Are my calculations right though?

I followed this and my answer is plausible but I think I am missing something in my calculations.


At the beginning of the year, balance = B.
interest = rate * B
B = B + interest
(or, alternatively B = B * (1+rate) )

Throughout the year, subtract the payment made each month from the balance:
B = B - payment (executed once each month)


Use these values:
Car Price: 30000
Age: 21
Interest Rate: 0.09
Deposit: 3000
Monthly Repayment: 400

You should get this:

year 1 remaining balance $25,720.00
year 2 remaining balance $23,234.80
year 3 remaining balance $20,525.93
year 4 remaining balance $17,573.27
year 5 remaining balance $14,354.86
year 6 remaining balance $10,846.80
year 7 remaining balance $7,023.01
year 8 remaining balance $2,855.08
--you will pay this off in 9 years


There is something missing in my calculations that doesn't get this exactly.
I don't know crap about loans and fancy business stuff.

I have not finished it yet so it won't be EXACTLY like what I have quoted but the values should be, that is my concern.

No matter how much I try I can't get them exact.

[netviper13]

I would assume interest is applied annually?

Just did some quick math on my graphing calculator, and using the info you gave I get a balance of $24,900 after the first year.

[Kruno]

How did you get 24,900?

Annual interest rate?

AFAIK Interest is calcualted on the balance outstanding at beginning of each year and credited to the loan amount to be repaid at this time.

[netviper13]

Ok, so if I'm understanding this correctly, the beginning balance is $30,000 right?

The first thing I did was calculate interest on that original amount (although that might be wrong since this is the first year of payment so there might not be interest yet) 30,000+(.09*30,000)=$32,700

Then I subtracted the deposit amount $32,700-$3000=$29,700

Then I took off the amount for monthly payments $29,700-(400*12)=$24,900

Of course that's not factoring in the VB code to do said calculations, but I'm assuming that once you get the formulas worked out you can code them. Anywho I'm off to bed for the night (1:35 AM here) so good luck in getting it.

[Kruno]

curInterest = curInterestRate * curBalance
curBalance = curBalance + curInterest
curBalance = (curBalance - (curMonthlyRepayment * 12)) - curDeposit


Thanks for reminding me about the deposit I had left it out. :o

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