The first year it decreased by 20%. Multiply the cost of the car by 80% ( 100%-20% = 80%)
24,000 x 0.8 = 19200
After the first year the car was valued at €19,200
Now divide the value after the 2nd year by the value after the first year:
16128 / 1900 = 0.84 * 100 = 84%
The car is 84% of the value.
100 - 84 = 16
The cars value decreased by 16% during the second year.
