Answer:
Adult's ticket is $9
Children's ticket is $6
Explanation:
let A be the adult's ticket and C be the children's ticket
2A + 6C = 54 equation1
7A + 3C = 81 equation2
multiply equation2 by -2
-2(7A + 3C = 81)
-14A - 6C = - 162 equation3
add equations 1 and 3
2A + 6C = 54
-14A - 6C = - 162
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-12A = - 108
divide both sides by -12
A = $9
substitute A = 9 to any of the equations, i'll use equation1
2A + 6C = 54
2(9) + 6C = 54
18 + 6C = 54
6C = 36
C = $6