Happy Tails Inc. has a September 1, 20Y4, accounts payable balance of $620, which consists of $320 due Labradore Inc. and $300 due Meow Mart Inc. Transactions related to purchases and cash payments completed by Happy Tails Inc. during the month of September 20Y4 are as follows:

Sept. 4. Purchased pet supplies from Best Friend Supplies Inc. on account, $295.

6. Issued Check No. 345 to Labradore Inc. in payment of account, $320.

13. Purchased pet supplies from Poodle Pals Inc. on account, $790.

18. Issued Check No. 346 to Meow Mart Inc. in payment of account, $300.

19. Purchased office equipment from Office Helper Inc. on account, $2,510.

23. Issued Check No. 347 to Best Friend Supplies Inc. in payment of account from purchase made on September 4.

27. Purchased pet supplies from Meow Mart Inc. on account, $450.

30. Issued Check No. 348 to Jennings Inc. for cleaning expenses, $80.

a. Prepare a purchases journal and a cash payments journal to record these transactions. The forms of the journals are similar to those used in the text. Place a check mark (✓) in the Post. Ref. column to indicate when the accounts payable subsidiary ledger should be posted. Happy Tails Inc. uses the following accounts:

Cash ..............................11

Pet Supplies .......................14

Office Equipment ...............18

Accounts Payable ...............21

Cleaning Expense ...............54

b. Prepare a listing of accounts payable creditor balances on September 30, 20Y4. Verify that the total of the accounts payable creditor balances equals the balance of the accounts payable controlling account on September 30, 20Y4.

c. Why does Happy Tails Inc. use a subsidiary ledger for accounts payable?