Sara's Systems manufactures audio systems for cars. Two models are produced: The Standard model has a budgeted price of $250 and a standard variable cost of $130. The Blaster model has a budgeted price of $530 and a standard variable cost of $210. At the beginning of the year, Sara estimated that she would sell 6,200 Blaster models and 24,800 Standard models. The actual results for the year showed that 7,460 Blaster models were sold for total revenues of $2,984,000. A total of 25,000 Standard models were sold for revenues of $6,750,000 

Required: 

a. Compute the activity variance for the year. 

b. Compute the mix and quantity variances for the year.