12-6 Consider a model thermodynamic assembly in which the allowed (nondegenerate) states have energies 0, ε, 2ε, 3ε. The assembly has four distinguishable (localized) particles and a total energy $U = 6\epsilon$.
(a) Tabulate the nine possible distributions of the four particles among the energy levels $n\epsilon$, where $n = 0, 1, \dots$
(b) Evaluate $w_k$ for each of the macrostates and calculate $\Omega = \sum_k w_k$.
(c) Calculate the average occupation numbers
$\bar{N_j} = \sum_k N_{jk} w_k / \Omega$
of the four particles in the energy states.