BackFill Systems allocates manufacturing overhead based on machine hours. Each connector should require $10$ machine hours. According to the static budget, BackFill expected to incur the following

$500$ machine hours per month $(50$ connectors $10$ machine hours per connector$)$

$$7,000$ in variable manufacturing overhead costs

$$9,560$ in fixed manufacturing overhead costs

During August, BackFill actually used $1,000$ machine hours to make $80$ connectors and spent $$5,800$ in variable manufacturing costs and $$7,800$ in fixed manufacturing overhead costs. BackFill's standa variable manufacturing overhead allocation rate is