A monopolist can sale 25 units of output per day for a price of k11.50 each and 26 units of output per day for a price of k11.50 each. The marginal revenue earned from the 26th units sold is

A monopolist can sale 25 units of output per day for a price of k11.50 each and 26 units of output per day for a price of k11.50 each. The marginal revenue earned from the 26th units sold is