Desperate help.reactor calculation exams question

Jan 2018
can some one help me here, This question is definately coming to my exams but do not understand it please. how you go the answer i would appreciate it please. please desperate help.

An open straight-blade turbine of diameter 0.82 m is used to stir
reaction mixtures in a 20 m3 batch with baffles. The mixture to be
stirred is composed of 15% NaOH solution with phenyl acetate reflux.
Given that the power of the agitator is fixed at 0.52 kW, how many
r/min of the turbine is possible?
Given that Po = 1.07; density = 1890 kg/m3; viscosity = 1.2 Ns/m2
(i) The r/min (rpm ) for the turbine.
(ii) Determine the emean value for the vessel. (iii) Would the agitation in the vessel be laminar, transitional or