preview 3 数学难题

if the market value of a car was 6000 exactly 3 year ago, waht is its current market value?
1. starting at the time of purchase, the market value of the car depreciated by 20 percent of its purchase price per year.
2.the current market value of a car manufactured in the same year is 2400

正确答案为E，为什么条件1不满足呢？

i suppose the "market value" is not the same meaning of "the purchase price".

such as property, whose market value depends on the valuator's judgement but not the price really paid to seller

just because the time of purchase is unknown