Three firms (players i, ii, and iii) put three items on the market and advertise them either on morning or evening tv. a firm advertises exactly once per day. if more than one firm advertises at the same time, their profits are zero. if exactly one firm advertises in the morning, its profit is $200k. if exactly one firm advertises in the evening, its profit is $300k. firms must make their advertising decisions simultaneously. find a symmetric mixed nash equilibrium.