For a piecewise linear graph of the fee structure based on the dog's weight, the x-axis should represent the weight of the dog. The appropriate scale would allow for clear representation of the different fee structures based on the weight ranges.
Given the structure:
- Dogs under 15 lbs.
- Dogs between 15 and 50 lbs.
- Dogs 50 lbs and over, with an increasing cost based on the additional weight.
The best choice for the quantity and scale for the x-axis would be:
weight; 10
This choice reflects the weight of the dogs in increments of 10 lbs, which aligns well with the ranges defined in the problem.