Answer:
Kailua and Company
Schedule of Cash Collections
August September
Cash collections from June $25,200 $0
Cash collections from July $38,500 $19,250
Cash collections from August $17,220 $43,050
Cash collections from September $0 $17,800
Total cash collections $80,920 $80,100
I suppose that 5% of the billings are uncollectible since 20% + 50% + 25% = 95%.