鲁教版七年级数学配套练习册习题7.5第五题答案

题目

鲁教版七年级数学配套练习册习题7.5第五题答案
王叔叔以两种方式分别储蓄了1000元和20000元,一年后全部取出,得利息457.2元.已知两种储蓄年利率为2.97%,求这两种储蓄的年利率.

答案

设1000元年利率为x,20000元年利率为（0.0297-x）.1000x+20000(0.0297-x)=457.21000x+594-20000x=457.2-18000x=457.2-594-18000x=-136.818000x=136.8x=0.00760.0297-x=0.0297-0.0076=0.02210.0076=0.76% 0.0221=2.21%...