One owes two bills of exchange with a face value of 30,000 euros and 20,000 euros, which expire in 65 and 75 days respectively, from today. He wants to replace them with a single bill of exchange value of 49,500 euros. In how many days from today he has to pay this bill? Interest rate 6%. mixed year, equivalence season 50 days from today.

That is exactly the question, I don't have to add something, as you don't say what you don't understand.