Maths Interest problem

Question
The annual depreciation rate of a car is 12%. If the value of the car is $95000 now, find the decrease in its value in the fifth year.

Solution
Now, time 0, value = $95000
One year later, time 1, value = $95000 * 0.88
Two years later, time 2, value = $95000 * 0.88²
Three years later, time 3, value = $95000 * 0.88³
Four years later, time 4, value = $95000 * 0.88⁴
Five years later, time 5, value = $95000 * 0.88⁵

Decrease in value in the fifth year
= Value at time 4 - Value at time 5
= $95000 * 0.88⁴ - $95000 * 0.88⁵
= $95000 * 0.88⁴ (1 - 0.88)
= $6836.527104

(B)

2013-11-11 23:20:20 補充：
阿月，要小心注意～

因為題目係問第五年減了多少～

〔有一題Physics題也是這樣考人，所以你做past paper時要注意～〕

2013-11-11 23:29:46 補充：
加油加油！！！！！！

2013-11-12 06:52:59 補充：
95000*0.88^5-95000 is the difference (-ve) between the value at time 0 and that at time 5.
This is the total decreased value for the WHOLE FIVE YEARS.

2013-11-12 06:53:36 補充：
95000*0.88^5-95000^4 is the difference (-ve) between the value at time 4 and that at time 5.
This is the decreased value for the FIFTH YEAR, as required by the question.

明白了, 理解錯咗,
好在有你提醒, 我下次會注意^^