Part A)
Let us first begin by understanding what Alejandro can read. We are told that he can read one page in one minute, so his rate or slope is 1pg/1min and we are told that he is starting at page 28 of his book, which is another way of saying that the y-intercept is 28. So, how can we put all of this information into the slope intercept formula (y=mx+b). We know that the number of pages Alejandro can read is dependent on the time that he can read them in, so pages is the y variable and time is the x variable. We can use all of this information to write the following formula
Pa = Ta +28
Now, lets follow the same reasoning to create an equation for Carly. We are told that Carly's rate is 2 pages per minute, or a slope of 2pgs/1min, and that she starts at page 12 of her book, or a y-intercept of 12. We can use this information to write the following formula
Pc = 2Tc +12
Part B)
Based on the above equations the rate of change, or slope, of Alejandro is 1pg/1min and the slope of Carly is 2pgs/1min.
Part C)
The rate of change in these situations represents the slope on a line.
Part D)
The y-intercept for Carly is 12 and it represents that she started reading at page 12.
Part G)
Alejandro has read more pages then Carly from 1 minute into reading to 15 minuets into reading because...
Ta +28 > 2Tc +12
We are going to assume that the times are the same since we are trying to find the maximum amount of time Alejandro can read and still be ahead of Carly. So...
T + 28 > 2T +12
T < 16
So, as long as Alejandro's time is less than 16 minutes, he will be ahead in the book.