Answer:
The children ticket cost is 8$
Explanation:
I. Given a = adult and c = children
10a + 10c = 200 => 1st day
13a + 2c = 172 => 2nd day
II. Multiply 2nd day with 5
65a + 10c = 860 => simulate
III. Eliminate c value by simulate - 1st day
55a + 0 = 660
a = 660/55
a = 12 or adult ticket cost is 12$
IV. Find children ticket cost by replace a value in 2nd day
13(12) + 2c = 172
156 + 2c = 172
2c = 172 - 156
c = 8 or children ticket cost is 8$
Hope that help :)