Answer: 160 children and 190 adults were admitted.
Explanation:
Let x represent the number of children that were admitted on that day.
Let y represent the number of adults that were admitted on that day.
On a certain day, 350 people entered the park. It means that
x + y = 350
The admission fee at an amusement park is 1.5 dollars for children and 4 dollars for adults. The admission fees collected on that day totaled 1000 dollars. It means that
1.5x + 4y = 1000- - - - - - - - - - -1
Substituting x = 350 - y into equation 1, it becomes
1.5(350 - y) + 4y = 1000
525 - 1.5y + 4y = 1000
- 1.5y + 4y = 1000 - 525
2.5y = 475
y = 475/2.5
y = 190
x = 350 - y = 350 - 190
x = 160