The Chilton Corporation specializes in manufacturing one type of desk lamp. Chilton allocates variable manufacturing overhead costs on the basis of machine hours. Chilton budgeted 0.5 machine hours per lamp and allocates variable overhead at a rate of $ 2.10 per machine hour. Last year Chilton manufactured 19 comma 000 lamps, used 114 comma 000 machine hours and incurred actual variable overhead costs of $ 171 comma 000. What was Chilton's variable manufacturing overhead rate variance last year?