We will call an adult ticket a, and a child ticket c.
Since they sold 60 tickets in total, we can form the equation:
a + c = 60
We can also say that the sum of money from the adult tickets and child tickets combined is 460.
Thus we can say
11a + 6c = 460
Now, we must solve our system.
a + c = 60
11a + 6c = 460
6a + 6c = 360
11a + 6c = 460
-5a = -100
a = 20
Thus, (20) + c = 60
c = 40
a = 20 and c = 40