So for the second table, we have to figure out the equation. I'll be putting the equation into slope-intercept form. (c = mp+b, m = slope and b = y-intercept).
To get the slope for the table, the formula is
. For this I'll be using (1,12.50) and (4,32).

Now that we have our slope, we can solve for the y-intercept. For this you need one of the points to replace the c and p placeholder, and for this I'll be using (2,19).

Now that we have all our info, we can form the Package B equation as such: c = 6.5p + 6
Now that we have both equations, just plug in 12 into the p placeholder for both and solve:


Assuming that our friend wants to save money, they should choose Package B.