Minden Company manufactures a high-quality wooden birdhouse that sells for $20 per unit. Variable costs are $6 per unit, and fixed costs total $180,000. During 2004, the company sold 24,000 birdhouses to customers. The president of Minden Company believes the following changes should be made in 2005: 1. the selling price of the birdhouse should be reduced by 10% 2. increase advertising by $30,000 Assume these changes are made. Calculate the number of units Minden Company must sell in 2005 in order to earn the same net income as earned in 2004