16.7% = 1/6
14.3% = 1/7
12.5% = 1/8
11.1% = 1/9
【解析】1/6 = 16.7%,1/7 = 14.3%,则15.4 = 1/6.5,N = 6.5。现期/N+1 = 80.1/7.5 = 10.7,选择B
【解析】5.1%=1/20
【解析】227-146 = 81,81 /5 =16.2,选择 D