Please help, I'm very confused as to what steps I need to take here to get the answer.

Calculate the required concentration of benzoyl peroxide (in the unit of g/cm3) for a polystyrene (PS) polymerization in order to obtain PS number-average molecular weight of 105 g/mol and the polymerization rate (in the unit of mole ms-). The known parameters are (1) the efficiency of initiator dissociation is 80%, (2) the rate constants of dissociation, propagation and termination are 2 x 10-6 s-1, 0.35 m3 mol-1 s-1, and 4 x 104 m3 mol-1 s 1, respectively, and (3) the densities of styrene is 0.85 g/cm3. Estimate how long it takes to have 90% of styrene being consumed (assuming steady state of radical)? If the disproportionation and chain transfer is negligible. 1 1 1