p=m/V=30g/[(65+30-83)g/1g/cm^3]=30g/12cm^3=2.5g/cm^3

问题描述:

p=m/V=30g/[(65+30-83)g/1g/cm^3]=30g/12cm^3=2.5g/cm^3

M=30g
总质量=65+30-83
密度=1g/cm^3