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?
a. 4c+7a = 376
c+a = 2120
a= 376-c
b. 7c+4a = 2120
a+c = 376
c. 4a+7c=2120
c+a = 376
d. 4c + 7a = 2120

The variable z is directly proportional to x, and inversely proportional to y. when x is 4 and y is 13, z has the value 1.2307692307692. what is the value of z when x= 9, and y= 20

Afair die is cast four times. calculate the probability of obtaining exactly two 6's round to the nearest tenth of a percent

Pleasseee important quick note: enter your answer and show all the steps that you use to solve this problem in the space provided. use the circle graph shown below to answer the question. a pie chart labeled favorite sports to watch is divided into three portions. football represents 42 percent, baseball represents 33 percent, and soccer represents 25 percent. if 210 people said football was their favorite sport to watch, how many people were surveyed?