We know that Profit = Earnings - Cost
Case 1: Sold as is
Profit = (300 fans* $20/fan) - (300 fans* $55/fan)
Profit = - $10, 500 (deficit)
Case 2: Processed further then sell
Profit = (300 fans* $90/fan) – [(300 fans* $55/fan) + (300 fans* $40/fan)]
Profit = - $1, 500 (deficit)
Since Case 2 has lower deficit, then it is better to process the fans further then sell to normal selling price.