The following information is related to manufacturing overhead costs. MOH cost pool includes depreciation (fixed, 10000 dollars per month), indirect material (variable, 2 dollars per unit) and supervision (semi-variable). During the last six months, the highest activity level was in May (1720 units produced) and total MOH cost was $35300. The lowest activity level was in March (1320 units produced) and total MOH cost was $31300. a.) Write the cost formula of supervision (use the high-low method). b.) Estimate Total MOH for July (1800 units produced) by using the data of the year's first six months.