Aging of receivables; estimating allowance for doubtful accounts

Wig Creations supplies wigs and hair care products to beauty salons throughout Texas and the Southwest. The accounts receivable clerk for Wig Creations prepared the following partially completed aging of receivables schedule as of the end of business on December $31,20$Y$7$:

Customer Balance Not Past

Due Days Past

Due $1-30$ Days Past

Due $31-60$ Days Past

Due $61-90$ Days Past

Due $91-120$ Days Past

Due Over $120$

ABC Beauty $20,90020,900$

Angel Wigs $7,0007,000$

Zodiac Beauty $4,4004,400$

Subtotals $1,281,800746,400282,800119,10037,40019,300$