Total MC(Q) is supposed to be Q(4/7)+4Need to understand why.

Three firms act as a cartel. That is, they jointly maximize industry profits by acting like a single monopoly with multiple plants. The cartel sets one per-unit price p > 0 for all consumers. The three cartel member firms have the following marginal cost functions. MC1(Q1) = 4Q1 MC2(Q2) = 2+2Q2 MC3(Q3) = 6+Q3 The inverse market demand is P(Q) = 64 - 4Q if Q