ANSWER
A. 9600 kg
EXPLANATION
Given:
• The volume of the substance, V = 12m³
,• The relative density of the substance, 0.8
,• The density of water, 1000 kg/m³
Unknown:
• The mass of the substance, m
The relative density of a substance is defined as,
[tex]\rho_{relative}=\frac{\rho_{substance}}{\rho_{water}}[/tex]And the density of a substance is,
[tex]\rho=\frac{m}{V}[/tex]Let's solve the first formula for the density of the substance,
[tex]\rho_{substance}=\rho_{relative}\cdot\rho_{water}=0.8\cdot1000\operatorname{kg}/m^3=800\operatorname{kg}/m^3[/tex]Then, solve the second formula for m,
[tex]m=\rho\cdot V=800\operatorname{kg}/m^3\cdot12m^3=9600\operatorname{kg}[/tex]Hence, the mass of this substance is 9600 kg
