First, let’s work out the problem to get an answer, then perhaps we can look at other ways of looking at and solving the problem.
To me this is simple proportion. If 2 pounds in weight costs $7.96, then 1 pound costs a half of this: $3.98. Therefore 5.5 pounds costs 5×3.98 (=$19.90) plus half of $3.98 (=$1.99) so 19.90+1.99=$21.89. So we have applied division, multiplication and addition to solve the problem this way.
The graphical method uses a straight line from which we can read off the cost of any weight of fajitas.
You can see that the resolution of the graph is too low to get an accurate solution, unless you increase the scale sufficiently to read two decimal places. But the graph is useful for seeing how the cost increases with weight. The equation of the graph is y=3.98x where y is the cost in dollars of x pounds of fajitas. When x=1, for example, y=4 approximately according to the graph. Actually, it’s 3.98, but the resolution of the graph doesn’t show this. When x=5.5, y=22 approximately, whereas the true answer is 21.89.
