The following represents the financial information for Domingo Corporation for two months.

	March		April
Sales revenue	$	480,000	$	430,000
Costs
Process inspection	$	1,650	$	1,850
Scrap		1,940		1,850
Quality training		20,300		12,300
Warranty repairs		4,400		5,000
Product testing equipment		6,600		7,300
Customer complaints		2,700		3,400
Rework		17,000		17,000
Preventive maintenance		14,700		8,800
Materials inspection		5,800		4,400
Field testing		9,400		14,300

Required:

a. Classify these items into Prevention, Appraisal, Internal failure, or External failure costs.

b. Calculate the ratio of the prevention, appraisal, internal failure, and external failure costs to sales for March and April.