The following are some of the operations that took place at Al Wahda Trading Company during the month of July 2016:
On 4/7	Purchasing goods from Al-Gharafa Company for 25,000 riyals, of which 5,000 riyals were paid by check and the rest on account and with conditions (2/10, p. 40).
On 7/7	Purchasing goods from Al Rayyan Company, the price of which according to the price lists is 10,000 riyals, and I paid their value immediately according to a bank instrument bearing the number 2182111 after obtaining a commercial discount of 10%.
On 12/7	Purchasing goods on account from Al-Sadd Company, the price of which according to the price lists is 30,000 riyals, obtained a commercial discount of 10%, and agreed with the seller on payment terms (2/10, p. 30).
On 13/7	it sold goods on account to Doha Company for an announced price of 20,000 riyals at a 10% trade discount and with conditions (10/3/, p. 30).
On 17/7	I received a notification from Doha Company stating that part of its goods that it purchased on 7/13 did not conform to the agreed upon specifications, so it was agreed to reduce the balance owed by Doha Company by an amount of 500 riyals in exchange for keeping the goods and not returning them.
On 20/7	It sold goods to Al-Wakra Company for 8,000 riyals on account and with conditions (2/8, p. 30).
On 21/7	It turned out that part of the goods purchased on July 7, worth 600 riyals according to the price lists, did not match the specifications, so it was returned and its value was received in cash.
On 21/7	Pay the amount due to the dam company with a check.
On 24/7	Pay the amount due to Al Gharafa Company with a check.
On 27/7	Collecting the amount due from Al Wakra Company by check.
On 28/7	Collecting the amount due from Doha Company with a check.
Required A) Proof of previous transactions in the unit companys books (assuming that the company uses the total invoice method to process the cash discount)