Question

为了加强公民的节水意识,某市制定了如下收费标准:每户每月的用水量不超过10t时,水价为每吨1.2元;超过10吨

Answer 1

(1)y=10*1.2+(x-10)*1.8=12+1.8*(x-10)

(2)12+1.8*(x-10)=30,求得x=20