Question

Alaina wants to decide whether her current cell phone plan is better than a package that another company offers. To compare the two plans, she plotted two lines on a graph, where y represented the total cost of one month’s service and x represented the megabytes of data that she used in a month. Which part of the graph will represent the cost per megabyte of data used in each plan?
The x-intercepts of the two lines
The y-intercepts of the two lines.
The slopes of the two lines.
The coordinates of a point of intersection.

Answer 1

Hello, this is a linear problem so we are working with y = mx + b

The problem tells us:

y = total cost

x = the megabytes of data that she used in a month

b = y-intercept, which is the initial value

The problem asks "Which part of the graph will represent the cost per megabyte of data used in each plan?"

It is asking for cost per megabyte... This is a rate. and m = slope = rate

So lets, reiterate.

y = total cost

x = the megabytes of data that she used in a month

b = y-intercept, which is the initial value

m = slope = rate = cost per megabyte of data used

Answer: The slopes of the two lines.