For this question, we will use the linear system of equations in order to find how many tickets were sold.
Let:
x = advance tickets
y = same-day tickets
x + y = 45
*this is because the total number of ticket solved was 45.
30x + 40y = 1550
*this is because the total amount of ticket sold was $1550
Using the linear system of equations, we can cancel out a variable. In this problem, let's try to cancel out x.
30x + 40y = 1550
x + y = 45
We multiply both sides of the second equation by -30 in order to cancel out x.
30x + 40y = 1550
-30x + 30y = 1359
This will leave us with
40y = 1550
30y = 1350
Subtract both equations and we will get
10y = 200
y = 20
Since we now have a value of y, we can now solve for the value of x.
Using x + y = 45;
x + (20) = 45
x = 45 - 20
x = 25
Going back, we know that
x = advance tickets
y = same-day tickets
Therefore, there are 25 advance tickets and 20 same-day tickets sold.