Goods costing $2,500 are purchased on account on July 15 with credit terms of 2/10, n/30

Goods costing $2,500 are purchased on account on July 15 with credit terms of 2/10, n/30. On July 18, a $200 credit memo is received from the supplier for damaged goods. Give the journal entry on July 24 to record payment of the balance due within the discount period using a perpetual inventory system.

Please explain all steps detally. I want to learn solving this type of exercises. How did you find the answer and with the help of which rule did you solve this exercise?

Please first write the answer of exercise and then detally explain. Please send me the answer in excel form to my mail: goodman24100@mail.ru