The value of a car after t years can be found using the formula v = c(1 - r)t, where v is the current value of the car, c is the original price of the car, and r is the rate of depreciation. solve the formula for r . raj bought a car 4.5 years ago for $25,000, and the current value of the car is $12,000. at what percentage rate has the car depreciated? round your answer to the nearest whole number.