OG12th PS 78

jessicasonia

Leona bought a 1-year, $10,000 certificate of deposit that paid interest at an annual rate of 8% compunded semiannually. What was the total amount of interest paid on this certificate at maturity?
A $10,464
B $      864
C $     816
D $     800
E $     480

主要是不太理解boldface部分 希望NN给我解答~！
THX~!!!

mandybabay

A = P* (1+ r/n)^(n/t).

P = 10,000
r = 0.08 (8%)
n = 2 (semiannually = 2, quarterly = 4)
t = 1 (one year)

jessicasonia

I GOT IT~!
THX

hjbb1027

相当于半年的compound rate是4%，一年之后就乘以（1+4%）^2,两年之后是（1+4%）^4

jessicasonia

呃 还是没太明白~~！
是(1+4%)的平方?

hjbb1027

就是说年利率是8%，每半年复合一次，一年就是(1+4%)^2