Gumchara Corporation reported the following information with respect to the materials required to manufacture amalgam florostats during the current month:

Standard price per gram of material	$4
Standard quantity of materials per amalgam florostat	5 grams
Actual materials purchased and used in production	6,000 grams
Actual amalgam florostats produced during the month	1,000 units
Actual cost of materials purchased	$18,000
Normal monthly output	900 units

a. Determine Gumchara's materials price variance

b. Determine Gumchara's materials quantity variance

c. Will Gumchara's overhead volume variance be favorable or unfavorable? Why?