Based on the information given the controllable variance is:$1,600.
Using this formula
Controllable variance=Actual total overhead -Budgeted total overhead at actual units produced
Let plug in the formula
Controllable variance=$12,000-$10,400
Controllable variance=$1,600
Inconclusion the controllable variance is:$1,600.
Learn more about the controllable variance here:https://brainly.com/question/24304293