SOLUTION
From the graph giving in the question, we just trace the point on the graph and locate the value on the y-axis
Considering the image below
Form the Image above
When the Monthly water usage is 22 HCF, tracing the yellow line we can see that
Therefore the residential plan cost more
The residential plan cost more by
Part B
Both monthly plans cost the same when the amount of the monthly water usage is
14 HCF
Since the line of the business plan is above the Residential plan before the line intercept, i.e between 2 HCF to 12HCF.
The business plan will cost more