Answer: 102 children and 41 adults swam at the pool that day.
Step-by-step explanation:
Let x represent the number of children that swam at the public pool that day.
Let y represent the number of adult that swam at the public pool that day.
On that certain hot summer's day, 143 people used the public swimming pool. It means that
x + y = 143
The daily prices are $1.25 for children and $2.25 for adults. The receipts for admission totaled $219.75. It means that
1.25x + 2.25y = 219.75- - - - - - - - -1
Substituting x = 143 - y into equation 1, it becomes
1.25(143 - y) + 2.25y = 219.75
178.75 - 1.25y + 2.25y = 219.75
- 1.25y + 2.25y = 219.75 - 178.75
y = 41
x = 143 - y = 143 - 41
x = 102
