eighth grade math

Question

On a certain hot​ summer's day,

312 people used the public swimming pool. The daily prices are $1.50 for children and $2.25 for adults. The receipts for admission totaled $669.75. How many children and how many adults swam at the public pool that​ day?

Answer 1

1.5c + 2.25a = 669.75

c +a =312

1.5c + 1.5a =1.5(312) = 468

subtract last from 1st equation

2.25a -1.5a = 669.75- 468

.75a = 201.75

a =201/.75=269 adults

c =312-269=43 children

check the answer

1.5(43)+2.25(269)

64.5+605.25= 629.75