Maximum force to pull two blocks without sliding

[Gravitational]

Homework Statement

A block of mass 2.0kg rests on top of another block of mass 10.0kg that itself rests on a frictionless table. The largest frictional force that can develop between the two blocks is 16N. Calculate the largest force with which the bottom block can be pulled so that both blocks move together without sliding on each other.

Homework Equations

The Attempt at a Solution

 

[TSny]

Please fill in items 2 and 3 as best you can.