So there's 2 types of depreciation you often will come across, one is compound and one is simple.
For compound : A=P(1-i)^n
For simple A=P(1-in)
NOTE: A is amount after depreciation, P is amount before depreciation, n is number of years and i is the rate of depreciation.
Now if your depreciation is compound then:
A=P(1-i)^n
A=28000(1- 0.09)^1
A= 25480
If it's simple depreciation
A=P(1-in)
A= 28000(1- 0.09x1)
A= 25480
Now these are your solutions