Project annual interest rate%

Demand deposit 0.99

Fixed deposit in lump sum and withdrawal

Three months 1.98

Half a year 2. 16

2.25 a year

Two years 2.43

2.70 pounds for three years

Five years 2.88

Lump-sum deposit and withdrawal, lump-sum deposit and withdrawal, lump-sum deposit and withdrawal, and interest withdrawal.

One year 1.98

Three years 2. 16

Five years 2.25

Fixed-income and double-income loans within one year shall be executed at a discount of 60% at the same grade interest rate.

(1) According to the way of education savings, how much is it to deposit in 50 yuan for three years every month, and what is the principal and interest that can be withdrawn in one lump sum when it is due (three years) or six years?

Arithmetic progression sum: S3 = 50 [36+(1+2+3+36) 2.7%/12] =1874.93 yuan;

S6 = 50 [72+(1+2+3+...+72) 2.88%/12] = 3915.36 yuan.

(2) According to the way of education savings, how much money can you save for three years a month, and you can withdraw the principal and interest in one lump sum when it expires (three years) or six years?

S3 = a (36+35+) ...+1) 2.7%/12 = a [36+6660 times 0.0225].

S6 = a (60+59+...+1) 2.88%/12 = a [72+26280 times 0.024].

(3) According to the way of education savings, 50 yuan saves for 3 years every month, and the principal and interest that can be withdrawn in one lump sum at maturity (3 years) is much more than the "lump sum withdrawal" of the same grade?

Withdrawal due (3 years): 50 (36+35+) ...+1) 2.16%/12 =1901.9.

Education savings S3 = 50 [36+(1+2+3+36) 2.7%/12] =1874.93 yuan;

The difference is 26.97 yuan.

(4) How much should I save every month if I want to withdraw all the principal and interest of my education savings at one time after 3 years?

A = 10000/(36+6662 times 70%/12) = 266.67733 = 266.68.

(5) If you want to withdraw all the principal and interest of education savings at one time after three years, how much should you save every month?

B = a 10000/(36+6662 times 70%/ 12) yuan.

(6) According to the way of education savings, it was originally planned to save 100 yuan per month for six years, but by four years, students need to withdraw all principal and interest in advance. How much principal and interest can they withdraw at a time?

S4 =100 [48+11760 times 0.0225] = 5064.60 yuan.

(7) According to the way of education savings, it was originally planned to save A yuan every month for 6 years, but by the time of B, students need to withdraw all the principal and interest in advance. How much principal and interest can they withdraw at a time?

This is a piecewise function: when b3, s = a [12b+(1+12b) 6b times 0.00225].

At 0<b<3, s = a [1+b times 0.99%].

(8) (Open-ended question): Save in other forms instead of education. Taking the monthly savings of 100 yuan and its use after 6 years as an example, this paper discusses the possible maximum income with the current interest rate standard, and compares the results with the education savings.

Education savings: S6 =100 [72+(1+2+3+...+72) 2.88%/12] = 7830.72 yuan.

One-year installment: s =100 [12+1361times198%/12] =12/kloc-0. After deducting 20% interest tax, the actual income is 10.22 yuan. The principal and interest will be transferred within 5 years:

D5 =1210.22 (1+52.88% 0.8) =1210.22 times1.

Sum of four years:1210.22 (1+32.7% 0.8) (1+2.25% 0.8) =1210.22 times/

Sum of three years: 12 10.22 times 1.0648 = 1288.64 yuan;

Total for the biennium:1210.22 (1+22.43% 0.8) =1210.22 times10.0388 =/kloc-0.

Annual payment: 12 10.22 times1.018 =1232.00.

Total: 6439.39+1210.22 = 7649.438+0 yuan.