Question

Identify the relationship between the cost and the weight of parmesan cheese using the given graph. Which of the following statements about the graph is correct?

• A. For $\$26,$ we can get $8$ oz of parmesan cheese.
  
• B. Cost (in $\$$) $=3$ x weight (in oz) $+1$
• C. None of the above
  
• D. The cost of $7$ oz of parmesan cheese is $\$20.$

Answer 1

The correct option is D The cost of $7$ oz of parmesan cheese is $\$20.$

Coordinates of point $A=(2,1)$
Coordinates of point $B=(5,2)$
Coordinates of point $C=(8,3)$

Cost (in $\$$), $x$	Weight (in oz), y	Relation
$2$	$1$	$2=3\times 1-1$ $x=3y-1$
$5$	$2$	$5=3\times 2-1$ $x=3y-1$
$8$	$3$	$8=3\times 3-1$ $x=3y-1$

The relation is cost (in $\$$) $=3\times$ weight (in oz) $-1$
So, option A is incorrect.

Now,
The cost of $7$ oz of parmesan cheese is $\$20.$
This means $y=7.$
Cost $=3\times 7-1$
$=21-1$
$=\$20$
So, option B is correct.

Option C
For $\$26,$ we can get $8$ oz of parmesan cheese.
This means $y=8.$
Cost $=3\times 8-1$
$=24-1$
$=23\ne 26$
Hence, option C is incorrect.