Answer and Step-by-step explanation:
[tex]We're~ asked ~to ~find ~the ~density ~of~ the ~rock, ~given ~some ~mass~ and~ volume \\information.[/tex]
[tex]We're ~given ~that~ the~ mass ~of ~the ~system ~before~ the ~rock ~was~ added\\ was ~120g. ~The~ mass~ after~the~ rock~ was~ added ~was~ 250 g,~ so ~the~ rock's\\ mass ~is:[/tex]
[tex]m_r_o_c_k=m_f_i_n_a_l-m_i_n_t_i_a_l=250g-120g=130g[/tex]
[tex]The~ initial~ volume ~of ~water~ in~ the~ graduated ~cylinder~ was~ 30mL,~ and~\\\ the~ volume ~after~ the ~rock~ was~ added ~read ~75mL, ~so ~the~ rock's~ volume~is:[/tex]
[tex]V_r_o_c_k=Vf_i_n_a_l-V_i_n_t_i_a_l=75mL-30mL=45mL[/tex]
[tex]\bold{The ~equation ~for~ the ~density~ of~ the~ rock ~is:}[/tex]
[tex]\boxed{~~Density=\frac{mass}{volume} ~~}[/tex]
[tex]\bold{And~ so~ we~ have:}[/tex]
[tex]Density=\frac{130g}{45mL} =\boxed{2.9g/mL=2.9g/cm^3}[/tex]
