As fast as possible really fast really fast
 
											 
											#1
[tex]\\ \rm\longmapsto Density=\dfrac{Mass}{Volume}[/tex]
#2
[tex]\\ \rm\longmapsto Mass=Density\times Volume[/tex]
[tex]\\ \rm\longmapsto Mass=120(0.75)[/tex]
[tex]\\ \rm\longmapsto Mass=90g[/tex]