Question 947503
A=Adult tickets; S=Student tickets
13A+2S=$78
13A+7S=$143 Subtract the two equations
-5S=-$65  Divide each side by -5
S=$13 ANSWER 1: Student tickets cost $13.
Substitute in one of the equations to find A, use the other to check:
13A+2S=$78
13A+2($13)=$78
13A+$26=$78 Subtract $26 from each side.
13A=$52  Divide each side by 13
A=$4 ANSWER 2: Adult tickets cost $4.
CHECK
13A+7S=$143
13($4)+7($13)=$143
$52+$91=$143
$143=$143