the library sells 376 books at its annual used-book fundraiser. They take in a total of $2120. Childrens books cost $4, and adults books cost $7. How many childrens books did they sell?

Let c = number of childrens books sold, and let a = the number of adult books sold.


which system of equations can the librarians use to solve this problem?

A4c+7a = 376

c+a = 2120

a= 376-c

B7c+4a = 2120

a+c = 376

C4a+7c=2120

c+a = 376

D4c + 7a = 2120