Vaughn, Incorporated, sold 12.000 units last year for $40.00 each Variable costs per unit were $8.00 for cirect materials, $8.00 for direct iabor, and $2.00 for variable overhead Fixed costs were $34,000 in manufacturing overhead and $21,000 in nonmanufacturing costs Required: a. What is the total contribution margin? b. What is the unit contribution matgin? Note: Round your onswer to 2 decimal ploces. c. What is the contribution margin ratio? Note: Round your intermediete colculations to 2 decimel ploces. d. If sales increase by 4,000 units, by how much will profits increase? Note: Round your intermediate colculations to 2 decimal ploces