Joyce Murphy runs a courier service in downtown Seattle She charges clients $0.54 per mile driven Joyce has determined that if she drives 3,000 miles in a month, her total operating cost is $795. If she drives 4,000 miles in a month, her total operating cost is $935 Joyce has used the high-low method to determine that her monthly cost equation is total monthly cost = $375 + $0.14 per mile driven Required: 1. Determine how many miles Joyce needs to drive to break even 2. Calculate Joyce's degree of operating leverage if she drives 4.200 miles 3. Suppose Joyce took a week off and her sales for the month decreased by 28 percent. Using the degree of operating leverage. calculate the effect this will have on her profit for that month