贴现息=票面金额 X 贴现率 X 贴现期年3.6% / 360=日贴现率贴现期4.6~5.10为24+10=34天贴现后金额等于票面金额减贴现息=30-30*3.6%/360*34=29.898万元
贴现后金额=30万-30万*3.6%*34/360=298980
=30万-30万*3.6%*90/360
