Question

the value of a machine depreciates 10% every year if its present value is 38700 find its value year ago

Answer 1

Let the value of the article 1 yr before be x
Therefore the present yr will be 9x/10
=38700=9x/10
=x=43000
And hence the present value =43000

And please mark me as brain list

Answer 2

43000
old value to new value-   -1/10
so new value to old value   +1/9