crane company accumulates the following data concerning a mixed cost, using units produced as the activity level. March units produced $8200$ adn total cost $14760.$ April units produced $7380$ and total cost $13650.$ May units produced $8610$ and total cost $15,234.$ june units prodcued $7210$ and total cost $13,414.$ july units produced $7790$ and total cost $14020$