47kg > 3x
47kg < 4x
=> 47kg/3 > x
47kg/4 < x
=> 47kg/4 < x < 47kg/3
11.有甲、乙兩個箱子,甲箱重47公斤1,其重量比乙箱的3倍還重,且比乙箱的4倍..-阿摩線上測驗