You budgeted to sell 20 units at a price of $5 per unit in 2020 . Budgeted variable costs were $3 per unit and budgeted fixed costs were $1.50 per unit. Actual numbers for 2020 are as follows: sales 24 units, price $4.50 per unit, variable costs $2.75 per unit, fixed costs $1.50 per unit. Compute sales volume variance: $12 favorable 4 units favorable $4 favorable $20 favorable $8 favorable