You might have lacking given information so you can re-check the given.
You are lacking the value of L (life of the car in years).
There are several types of depreciation formulas. The straight-line method, sinking fund method, declining balance and double-declining balance. For the other methods you can search it up.
I used the sinking fund method for this case:
d = \frac{(25000 - 0)*0.15}{(1+0.15)^{L} -1
where d is the annual cost of depreciation
Co is the original cost,
\(C_{L}\) is the value at the end of the life of object or salvage value
L is useful life of the property
and i is the interest rate.
The salvage value can be assumed as zero in this case, therefore,
\(d = \frac{(25000 - 0)*0.15}{(1+0.15)^{L} -1}\)
In solving for the expected depreciation one can use this formula:
\(D_n = d*\frac{(1 + i)^{n}-1 }{i}\)
where n is the number of years of the expected depreciation
D_n is the depreciation up to the number of years (n)
