Pulling blocks on a Rough Table

A person pulls some blocks resting on a table with friction by means of a rope as shown. The coefficients of friction between the bottom block and the table are $\mu_s(bt) = 0.5$ and $\mu_k(bt) = 0.3$. The coefficients of friction between the blocks themselves are $\mu_s(bb) = 0.2$ and $\mu_k(bb) = 0.1$. The mass of the blocks is $m_1 = 6$ kg and $m_2 = 3$ kg. The blocks are initially at rest.

Find:

a) The minimum tension in the rope such that the blocks start to move.

b) Suppoe that the tension in the rope is 54 N (bigger than the minimum tension needed to start the blocks moving). Find the acceleration of both blocks. (Do they move together or separately?)