if the total cost of x apples is b cents, what is a general formula for the cost ,in cents,of y apples?

Question

this is pre algebra for placement test.

Answer 1

Try starting with a proportion. Let K be the cost we are looking for.

b / x = K / y

Now solve for K.

K = by / x

Answer 2

cost of x apples=b cents
cost of 1 apple=b/x cents
cost of y apples=y*b/x

Answer 3

cost=yb/x