Answer: $7,864.32
Explanation:
First you would do 100% -20% which would give you 80% (0.8)
1st year : $24,000 x 0.8 = 19,200
Then take your answer and times it by 0.8 again until you get to the 5th year
2nd year : $19,200 x 0.8 = $15,360
3rd year : $15,360 x 0.8 = $12,288
4th year : $12,288 x 0.8 = $9,830.40
5th year : $9,830.40 x 0.8 = $7,864.32
Therefore your final answer is $7,864.32