Gribble Company's high and low level of activity last year was 60,000 units of product produced in May and 20,000 units produced in November. Machine maintenance costs were $156,000 in May and $60,000 in November. Using the high-low method, determine an estimate of total maintenance cost for a month in which production is expected to be 45,000 units. a. $135,000 b. $144,000 c. $117,000 d. $120,000 D10: Rin AP Mam MinAACSR Anal AICPA RR Industarter Pannen AICPA FN: Mement AICPA PC Dunbar Manufacturing's variable costs are 30% of sales. The company is contemplating an advertising campaign that will cost $55,000. If sales are expected to increase $100,000, by how much will the company's net income increase? a. $45,000 b. $70,000 c. $30,000 d. $15,000 pa