某商店运来一批电动车,卖出50辆,又运进120辆,现在比原来多20%,原来运进多少辆电动车?
(120-50)÷20%,
=70÷0.2,
=350(辆);
答:原来运进350辆电动车.
基线丈量的精度用相对误差来衡量,其表示形式为()
A.平均值中误差与平均值之比
B.丈量值中误差与平均值之比
C.平均值中误差与丈量值之和之比
My mother didn’t know how to care for her own home and children.