The manaoer at Mounds of Mulch has been trying to caloulate the porfon of the company's overtead erpenses that is fired and the porfon that is varlable. Over the past weive months, the number of yards of mulch processed was highent in July, when the lotal monkly overhead cos's lotaled $31,000 lor 30,000 yards of mulch processed. The lowest rimber of yards of mulch processed in the tast taelve months oocured in oclobec, when fotat ovechesd costs were $24,000 for 23,000 yards of mulch processed. What was the variable cost jer yard