利率是百分之幾

每年利息:
$1000/4
=$250
每年利率:
$250/$5000
=5%

2006-11-11 15:36:37 補充：
四年總利息:$6000-$5000=$1000This is the first step

I think you are asking simple interest 單利息.
use the formula, A = P(1+rn%)
6000 = 5000(1+4r%)
r = 5
年利率is 5%

If you are asking compound interest 複利息
then the formula is A = P(1+r%)^n
6000 = 5000(1+r%)^4
r = 4.66
年利率is 4.66%

(6000/5000)^(1/4) - 1 = 4.66% p.a.

5000 * (1+P)^4=6000
1+P=(6000/5000)^(1/4)
P=0.0466=4.66%

2006-11-11 15:41:42 補充：
這是覆息計算。"^" 是 "次方"1/4 是 "開4次方根"

陳先生在02年把$5000存入銀行。四年後他連本帶利總共有$6000，如果這四年來利率保持不變，問每年利率是百分之幾?
Let X be the interest(利率) every year
5000(X%)(4)=6000-5000
20000(X%)=1000
X%=0.05
So 每年利率是5%