Answer:
94 Child tickets were sold.
Explanation:
Let x represent child tickets 
 
Let y represent adult tickets 
 
Cost Equation: 5.70x + 9.75y = 1306.10 
 
Quantity Equation: x + y = 173
Multiply the Quantity Equation by -5.70
 5.70x + 9.75y = 1306.10
 -5.70x - 5.70y = -986.10
 4.05y = 320.00
 ÷4.05 ÷4.05 
 y = 79
x + y = 173
x + 79 = 173
x = 94