Maths

Let the interest rate be y% per year, then

Principal + Interest = Amount
Principal + Principal x Interest Rate x Period = Amount
7000 + 7000 x y% x 10 / 12 = 7350
7000 x (y / 100) x (10 / 12) = 7350 - 7000
70 y x (10 / 12) = 350
700y / 12 = 350
700y = 350 x 12
2y = 12
y = 6

(7350-7000) 除12份之10乘100%

2006-11-09 20:47:02 補充：
唔好意思...係除100至岩!!!~

English:
Stores 7000 Yuan take out when has 7350 Yuan to deposit for 10 months namely compared to before many 350 Yuan; Because has only deposited for 10 months,Insufficient year,Therefore is 10÷12;
Asks the annual interest rate to want ÷100%
therefore the formula is:
(7350-7000)÷(10÷12) ÷100%
=350÷(5/6)÷100%
=350x(6/5)÷100%
=420÷100%
=4.2%


Chinese:(中文)
存入7000元
取出時有7350元
存放了10個月
即比之前多了350元;
由於只存放了10個月,不足一年,所以是 10÷12;
求年利率要÷100%
所以式子是:
(7350-7000)÷(10÷12) ÷100%
=350÷(5/6)÷100%
=350x(6/5)÷100%
=420÷100%
=4.2%

Let x be the interest rate per year, i.e. 12 months

7000 * (1 + x * 10/12) = 7350
1 + x * 10/12 = 1.05
x * 10/12 = 0.05
x = 0.06
x = 6%