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An equipment costing P 250,000 has an estimated life of 15 years with a book value of P 30,000 at the end of the period.
Compute its book value after 10 years using declining balance method.
a. P 68,656.25 b. P 59,987.34 c. P 60,234.50 d. P 60,832.80
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The solution in the post by @CPhill is incorrect.
In his solution, he takes " the interest rate " value as 0.08 in ABSOLUTELY ARBITRARY way:
the problem does not contain this value.
In opposite, the depreciation rate should be found from the problem's data,
and its proper finding is the of the solution.
See my correct solution below.
We use exponential function for the declining current cost of the equipment
C(t) = , (1)
where 't' is time in years.
Since the initial cost is P 250,000, we have a = 250000 in this formula.
Since the book value is P 30,000 in 15 years, we have this equation
30000 = ,
which gives
= ,
= ,
Take logarithm of both sides
log(3/25) = 15*log(b)
log(b) = = -0.061387917.
Hence, b = = 0.86818461.
Now we are in position to answer the problem's question using formula (1)
C(10) = = 60822.01984
The closest option in the answer list is (d).
Solved correctly.
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Notice that I do not use a "sinking fund" conception or functions in this problem,
because they are irrelevant to this problem.
I use a classic standard depreciation exponential model.