at a theme park, the admission price for children is $7 and the admission price for adults is $21. The total amount the theme park collects in admissions for the day is $5439. The total number of visitors is 305. let c be the number of children and let y be the number of adults. which system represent the situation
21x+7y=5439
x+y=305
7x+21y=5439
x+y=305
x+y=5439
21x+7y=305
x+y=5439
7x+21y=305