How do you find the acceleration of block B

[houssamxd]

Homework Statement

Block A sitting on top of block B
has a mass mA = 10 kg and is attached to the wall by mass less string.
Block B, mass mB = 35 kg, is pulled by a force F = 80 N. The surface
under block B is frictionless. If the coefficients of friction for block A
and B areμs = 0.4 and μk = 0.1, then the acceleration (in m/s2) of
block B is

Homework Equations

ma=sigma(F)

The Attempt at a Solution

i got my answer as 1.2
but its wrong

 

[tiny-tim]

hi houssamxd!

show us your full calculations, and then we'll see what went wrong, and we'll know how to help!