Answer:
Let c be the number of children and a be the number of adults.
1.75c + 2.25a = 1,180->1.75c + 2.25a = 1,180
c + a = 574->1.75c + 1.75a = 1,004.5
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.5a = 175.5
a = 351, so c = 223
So there were 351 adults and 223 children that day.