Identify dependent & independent variables

You are buying boxes of cookies at a bakery. Each box of cookies costs $\$4$. In the graph below, $c$ represents the number of boxes of cookies you buy, and $d$ represents the amount the cookies will cost you (in dollars). The relationship between these two variables can be expressed by the following equation: $d=4c$. Suppose the boxes of cookies cost you $\$80$. **How many boxes of cookies did you buy?** [[☃ input-number 1]] boxes