Question

Based on the graph, how would 20 cookies cost? Show your workDoes the graph show a proportional relationship?(And the number of 1 cookie is $0.25)

Answer 1

Start identifying the proportionality constant using one of the points of the graph, then:

`\begin{gathered} y=k\cdot x \\ 2=k\cdot8 \\ k=(2)/(8) \\ k=(1)/(4) \end{gathered}`

then, use the value found to obtain the cost for 20 cookies

`\begin{gathered} y=(1)/(4)x \\ y=(1)/(4)\cdot20 \\ y=5 \end{gathered}`

20 cookies cost $5.00

Finally, we can find the graph corresponds to a proportional relationship since it is a straight line and it also passes through the origin