Answer:
1. Account balance on February 1:
= Payments made + Closing balance - Purchases
= 186,500 + 59,900 - 201,400
= $45,000
2. Fees billed to customers on account in October:
= Amount collected from customers + Closing balance - Opening balance
= 449,600 + 130,770 - 115,800
= $464,570
3. Cash payments in April:
= Opening balance + Cash receipts - Closing balance
= 46,220 + 248,600 - 56,770
= $238,050