Murrah Company accumulated the following data concerning a mixed cost using miles as the activity level. January: 60,000 miles; total cost - $219,000 February: 80,000 miles: total cost - $275,000 March: 50,000 miles; total cost - $186,000 April: 90,000 miles; total cost - $308, 400 Using the high - low method, what is the unit variable cost? $2.70 per mile $2.81 per mile $2.94 per mile $3.06 per mile