maths問題(20分)

7a. 20,000 x 6% x 2=2,400.
7b. [20,000 x (1+3%)^4] - 20,000 = 2,510. Thus, 110 dollars more.
8a. 2,500,000 x (1+1%)^48 = 4,030,565.
8b. 3,500,000 x (1+13%)^4 = 5,706,658.
8c. gain = 5,706,658 - 4,030,565 = 1,676,093.
9a. 20,000 x (1+2%)^12 = 25,365.
9b. (25,365-20,000)/20,000 x 100% = 26.8%
10. Taxable income = 180,000-100,000 = 80,000
Tax payable = 35,000 x 2% + 35,000 x 7% + 10,000 x 12% = 4,350.
11a. A = 100,000 x (1+0.5%)^36 - 100,000 = 19,668.
B = 100,000 x (1+1.65%)^12 - 100,000 = 21,699.
Therefore, B earns more interest.
11b. Difference in interest = 21,699 - 19,668 = 2,031.

Question 7: A: $2400
B: I don't know
Question 8: A: $12000000
B: $1820000
C: I don't know