Suppose a firm's production function is given by Q = 12L - L^2 for L = 0 to 6, where L is labour input per day and Q is output per day. Derive and draw the firm's demand for labour curve if the output sells for $10 in the competitive market. How many workers will the firm hire when the wage rate is $30 per day? (Hint: The marginal product of labour, MPL is 12 - 2L).