求教：ttGWD 19-10

这题的答案是D？我认为不对。根据(2)的条件r应该可以<8吧，例如7.96啥的。

到底是选A还是D呢？

Q10:

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

顶！

那位xdjm讨论一下？

A?

(1+x)**2=1+2x+x**2>1.15

2x+x**2>0.15 but 2*0.08=0.16 so.. can't decide x>0.08 or not.