Pleiss Corporation applies manufacturing overhead to products on the basis of standard machine-hours. The company's cost formula for variable overhead cost is $2.40 per machine-hour. The actual variable overhead cost for the month was $5,240. The original budget for the month was based on 2,100 machine-hours. The company actually worked 2,270 machine-hours during the month. The standard hours allowed for the actual output of the month totaled 2,280 machine-hours. What was the variable overhead efficiency variance for the month?