Hello, thank you for taking the time to post your question!
The key on this type of question is to set up a system of equations that models the information given to us in the question. On this one we have
x + y = 6000 (since there are 6000 tickets sold in total)
27x + 40y = 181500 (the 27 and 40 are the ticket prices, 181500 is the total revenue)
I would take the first equation and plug in y = 6000 – x into the second equation and solve for x algebraically. When I do that I get that
4500 tickets were sold at $27 and
1500 tickets were sold at $40
I hope that helps get you moving in the right direction! Feel free to reach out if you have any additional questions beyond that :)