Question

a car deceased in value by 25% in the first year. purchased for $28,000, what is the car worth today.

Answer 1

Try this:  Principal times (1+interest rate as a decimal fraction)^(number of yrs)

In this case, Principal = $28,000; interest rate = -0.25; # of years = 1

So Decrease in value = $28,000 (0.75)^1 = $21,000.