The Smart Garage Company uses standards to control the labour time and labour cost in the shop. The standard labour cost for a motor tune$-$up follows:

$\backslash$table$[[,$Standard,Standard,Standard$],[$Job$,$Hours,Rate,Cost$],[$Motor tune$-$up$,3,$$$4,$$$12$

The record showing the time spent in the shop last week on motor tune$-$ups has been misplaced. However, the shop supervisor recalls that $31$ tune$-$ups were completed during the week, and the controller recalls the following variance data relating to tune$-$ups:

$\backslash$table$[[$Labour rate variance,$$94F$