Let x = # of tickets sold at $50. Then the number of tickets sold at $20 was 3x, according to the condition, and the rest, (5000-x-3x) were sold at $30. Therefore, your "money" equation is 50x + 20*(3x) + 30*(5000-x-3x) = 140000 dollars total (the revenue !). 50x + 60x + 150000 - 120x = 140000 -10x = 140000 - 150000 = -10000 x == 1000. Answer. 1000 tickets at $50; 3000 tickets at $20 and 1000 tickets at $30.