A = the number of adult tickets
S = the number of student tickets
[you can use different variables x, z, t, etc...]
5A + S = 2783 [$5 per adult plus $1 per student = total $2783]
A + S = 1235 [# of adults plus # of students = 1235]
To find A and S, you need to do substitution. First isolate one of the variables using either one of the equations, I will isolate the A in A + S = 1235:
A + S = 1235 Subtract S on both sides of the equation
A = 1235 - S
Next substitute/plug in (1235 - S) for A to find the value of S:
5A + S = 2783 [isolate/get S by itself in the equation]
5(1235 - S) + S = 2783 Distribute/multiply 5 into (1235 - S)
(5)1235 - (5)S + S = 2783
6175 - 5S + S = 2783 Combine like terms (-5s and S)
6175 - 4S = 2783 Subtract 6175 on both sides
-4S = -3392 Divide -4 on both sides
S = 848
Now that you found S, you can use it to find A:
A + S = 1235
A + 848 = 1235 Subtract 848 on both sides
A = 387
S = 848 student tickets
A = 387 adult tickets
