Answer: 400 adult tickets were sold.
Step-by-step explanation:
Let x represent the adult tickets that were sold.
Let y represent the number of children tickets that were sold.
1000 tickets were sold to the seaport aquariums dolphin show. This means that
x + y = 1000
Adult tickets cost $10. Children tickets cost two dollars and a total of 5200 was collected. This means that
10x + 2y = 5200 - - - - - - - -1
Substituting x = 1000 - y into equation 1, it becomes
10(1000 - y) + 2y = 5200
10000 - 10y + 2y = 5200
- 10y + 2y = 5200 - 10000
- 8y = - 4800
y = - 4800/ - 8
y = 600
x = 1000 - y = 1000 - 600
x = 400
