The Hayes Chemical Company produces a chemical used in dry cleaning. Its accounting system uses standard costs. The standards per .5-gallon can of chemical call for 1.20 gallons of material and 1.50 hours of labor. (1.20 gallons of material are needed to produce a .5-gallon can of product due to evaporation.) The standard cost per gallon of material is $6.00. The standard cost per hour for labor is $9.00. Overhead is applied at the rate of $7.75 per can. Expected production is 20,000 cans with fixed overhead per year of $55,000 and variable overhead of $5.00 per unit (a .5-gallon can). During 2021, 23,000 cans were produced; 35,000 gallons of material were purchased at a cost of $250,000; 30,000 gallons of material were used in production. The cost of direct labor incurred in 2021 was $290,000 based on an average actual wage rate of $8.25 per hour. Actual overhead for 2021 was $220,000. 

Required 

a. Determine the standard cost per unit. 

b. Calculate material, labor, and overhead variances. 

c. List a possible cause for each variance.