There is a proportional relationship between the number of oatmeal raisin cookies Jane buys, x, and their total cost (in dollars), y.

x (cookies) y (dollars)

6 $ 6

8 $ 8

15 $ 15

18 $ 18

Write an equation for the relationship between x and y.

y=

Given proportional relationship between the number of oatmeal raisin cookies Jane buys, x, and their total cost (in dollars), y shows you that

y=x.

You can check it:

when x=6 cookies, then y=$6 (x=y); when x=8 cookies, then y=$8 (x=y); when x=15 cookies, then y=$15 (x=y); when x=18 cookies, then y=$18 (x=y).

Answer: y=x.