Depreciation  different results on HP30b and on paper

03122021, 12:05 AM
(This post was last modified: 03122021 12:11 AM by FabioBrasil.)
Post: #1




Depreciation  different results on HP30b and on paper
Hello.
I come again to kindly ask for help from you who know a lot about HP. I cannot make the result of the calculation of decreasing depreciation (DecBal) provide the same result on the HP30b calculator and on paper. The problem consists of the following:  Cost (Czero)= $ 25000  Salvage = $ 5000  Life = 15 years  Factor =10.174% On paper D (n) = Czero * (1 Factor) ^ n in year 1 I have 22,456.50 in year 3 I have 18,119.49 in year 6 I have 13,132.64 in year 12 I have 6,898.65 (n = year use as Factor 10.174%) On the HP30b calculator (use as Factor 10.174%): in year 1 I have 24,830.70 (R.Book) in year 3 I have 24,494.94 in year 6 I have 24,000.08 in year 12 I have 23,040.16 Where am I going wrong? I couldn't get the answer on the Learning Modules. Thanks! 

03122021, 05:13 PM
Post: #2




RE: Depreciation  different results on HP30b and on paper
Methods of Depreciation: Formulas, Problems, and Solutions
Straight Line Method Declining Balance Method Declining Balance Method is sometimes called the ConstantPercentage Method or the Matheson formula. The assumption in this depreciation method is that the annual cost of depreciation is the fixed percentage (1  K) of the Book Value (BV) at the beginning of the year. Annual Rate of Depreciation(K): SV = FC (1  K)^{n} source:Depreciation Methods in Engineering Economics Any SME's with the formula/equation deployed in the HP30B ? BEST! SlideRule 

03122021, 05:33 PM
Post: #3




RE: Depreciation  different results on HP30b and on paper
(25000  5000)*(1  10.174/1200) + 5000 = 24830.43
So it would seem it works per month i.o. per year. Werner 41CV†,42S,48GX,49G,DM42,DM41X,17BII,15CE,DM15L,12C,16CE 

03122021, 05:47 PM
Post: #4




RE: Depreciation  different results on HP30b and on paper
(03122021 12:05 AM)FabioBrasil Wrote: Hello.It looks like your paper version is correct. Code:
Tom L Cui bono? 

03122021, 06:50 PM
Post: #5




RE: Depreciation  different results on HP30b and on paper
FabioBrasil
Did we help you answer your question? BEST! SlideRule 

03132021, 12:32 AM
(This post was last modified: 03132021 12:33 AM by FabioBrasil.)
Post: #6




RE: Depreciação  resultados diferentes no HP30b e no papel
Thank you for your help! It is good to have good people.


03132021, 04:25 AM
(This post was last modified: 03132021 05:15 AM by paul0207.)
Post: #7




RE: Depreciation  different results on HP30b and on paper
Fabio,
This is how I get the same answer on the HP12c (I don't have an hp30b to check it out, sorry). 25000 > PV 15 > n 152.61 > i (that is 10.174 * 15) Both PMT and FV = 0. Then 1 DB yields 2543.50 x<>y 22456.50 (which is your first year answer on paper). Summing up, try i=152.61 (i*n) on the hp30b for the Declining Balance method. Hope this helps, Paul 

03132021, 12:15 PM
Post: #8




RE: Depreciation  different results on HP30b and on paper
(03132021 04:25 AM)paul0207 Wrote: Summing up, try i=152.61 (i*n) on the hp30b for the Declining Balance method. Yes! This is from HP12C Appendix D, formula used for DecBal: DPN_{j} = RBV_{j1} * FACT / (100L), for j = 1, 2, ..., L We can also consider DecBal as TVM problem, with negative interest rate: 10.174 [CHS] [I] 25000 [CHS] [PV] 0 [PMT] Book values, for different years: 1 [N] [FV] → 22456.50 3 [N] [FV] → 18119.50 6 [N] [FV] → 13132.65 12 [N] [FV] → 6898.66 15 [N] [FV] → 5000.01 We can derive book value formula directly, by fitting the power law: book_value / cost = (salvage / cost) ^ (years / life) when exponent = 0, book_value = cost when exponent = 1, book_value = salvage For above example, we have: book_value = 25000 * 0.2 ^ (years/15) 

03142021, 09:04 PM
Post: #9




RE: Depreciação  resultados diferentes no HP30b e no papel
Paul0207, Thank you very much!
You solved the problem with Factor = rate * lifetime. In the Declining Balance mode (DecBal) this made me arrive at the same values of the exercise. Many, many thanks to all the colleagues who taught me a lot! Paul0207, most things are the same on the HP12C and the HP30b. So much the same, that I use programs written for the HP12c on the HP30b with few modifications. And you don't need to apologize for anything, I appreciate your help! 

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