GWD-19-Q10请教

If $1,000 will be deposited in a bank account and I is the dollar amount of interest earned from the original deposit, represented as I = 1000 {(1 + r/100)ⁿ – 1}, and the annual interest rate is r percent, is r > 8 percent?

(1)   The deposit earns a total of $210 in interest in the first 2 years.

(2)     (1 + r/100)² > 1.15

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

答案是选D, 但是我算出来，第二个好像不能满足>8%，V1.15大小介于1.07-1.08之间呀，可能是方法有问题，请NN指教呀！！

for 2)

i got r^2 + 200r -1500 >0

(r+50)(r-30) >0  so B works too..

-open to discuss -

Thank u Amacd for your answer

but u can't get 200r by adding 50r to 30r