Formulas and steps in solving this question?

Use the following information to answer the next question(s). The following information was collected regarding maintenance costs at different activity levels measured in machine hours: Number of Machine Hours 8,000 10,000 11,000 9,000 14,000 12,000 Total Maintenance Costs $600,000 640,000 800,000 700,000 900,000 870,000 13) Using the high-low method, an estimate of the variable component for maintenance costs is A) $64.28. B) $52.50. $75.00. D$50.00 14) Using the high-low method, an estimate of the fixed portion of maintenance costs is A) $165,000. B) $224,000. C) $300,000. (D) $200,000. 15) Using the cost formula developed under the high-low method, what would be the estimate of maintenance costs if 13,000 machine hours are scheduled for next month A) $950,000. B) $882,000. C) $650,000. 850,000