Friction pulley problem?

Question

.............___|_A_|_---------O--|
P <-----|_B_40kg_|--------O..|
it's a single pulley connected to the two blocks and connected by its center to the wall. Block A is on top of block B with block B being pulled straight to the left (P)
u = 0.2 at all contact surfaces (neglect pulley friction)
A is 80kg
Determine the magnitude of force P required to move the 40kg plate B to the left.

the answer they gave is 549 N, I can't get that using that equations

Answer 1

F= fab + fa or let a=1 and f=2 then
F= f1,2 + f1
fab= u(m1+ m2)g
fa=u(ma)g

F= ug(m1 + m1 +m2)
F=ug(2m1+ m2)
F= 0.2 x 9.81 (2x80 + 40)
F=390N