Answer: 48.83%
Explanation: Mass percent is the ratio of mass of the particular substance to the total mass of given compound.
[tex]{\text {mass percentage}}=\frac{\text{mass of }MgSO_4}{\text {total mass}}\times 100\%[/tex]
Mass of [tex]MgSO_4[/tex]= 120g
Mass of [tex]MgSO_4.7H_2O[/tex]= 246g
[tex]{\text {mass percentage}}=\frac{120g}{246g}\times 100\%=48.83\%[/tex]
