Let x = price of a senior ticket and y = price of a child's ticket
x + 2y = 37
14x + 13y = 323
From the first equation, x = 37-2y
Substitute for x in the other equation to get 14(37 - 2y) + 13y = 323
-15y = -195
y = 13 and x = 11
Each senior ticket costs $11 and each child's ticket costs $13.