purchases of inventory on account

Stober Corporation made two purchases of inventory on account during the month of March. The first purchase was made on March 5 for $30,000, and the second purchase was made on March 10 for $60,000. The terms of each purchase were 2/10, n/30. The first purchase was settled on March 13, and the second was settled on July 18.
REQUIRED:
a. Prepare all the necessary journal entries associated with these transactions.
b. Assume that with respect to the second purchase, the company settled two-thirds of the accounts payable balance on March 19 and settled the remaining balance on August 7. The first purchase was settled on March 13. Prepare all the necessary journal entries associated with the second purchase.