The library sells 500 books at its annual used-book fundraiser. They take in a total of $3940. Children's
books cost $5, and adult books cost $9. How many
children's books did they sell?
Let e = number of children's books sold, and Let
a= the number of adult books sold.
Which system of equations can the librarians use to
solve this problem?
A.
5c+9a=500
c+a=3940
c+a=500
C.
5c+9a=3940
B.
a=500-c
9c+5a=3940
a+c=500
D.
5a+9c=3940

An optical inspection system is used to distinguish among different part types. the probability of a correct classification of any part is 0.92. suppose that three parts are inspected and that the classifications are independent. let the random variable x denote the number of parts that are correctly classified. determine the probability mass function of x. round your answers to four decimal places (e. g. 98.7654). x f(x) 0 1 2 3

Tabby sells clothing at a retail store, and she earns a commission of 6.25% on all items she sells. last week she sold a pair of jeans for $32.50, a skirt for $18.95, and 2 blouses for $14.95 each. what was tabby's total commission? a $4.15 b $5.08 c $81.35 d $348.60

Which one is the correct answer, and why?