the population of snowtown was 4500 in 1990.In 1994,it had decreased to 3600.Find the percent decrease in population during those four years.如果有公式也一起给我,给个详解
问题描述：
the population of snowtown was 4500 in 1990.In 1994,it had decreased to 3600.Find the percent decrease in population during those four years.如果有公式也一起给我,给个详解
答
（1-x)^4*4500=3600 x=5.43% 设X是年降低率 1991年的人口是（1-x)*4500 1992年是1991年人口*（1-x)=(1-x)^2*4500 以此类推
答
。。。。。。。。。。。。。。看不太懂。懂
答
原意：1990年……的人口是4500人,在1994年则下降到3600.求下降率.
（4500－3600）/4500＝20％