1. Find the slope of the line that goes through donuts 1-12.
take the points
(1, 1.05) and (2, 2.10)
m=(2.10-1.05)/(2-1)
m=1.05/1
m=1.05
Find the slope of the line that goes from donuts 13-25
take the points
(14,14.05) and (15, 15.10)
m=(15.10-14.05)/(15-14)
m=1.05/1
m=1.05
so
The slope is the same
2. What if we only buy in amounts of baker's dozens? Is there a line for those? What points are on this line? What is the slope?
the points are
(13,13.00) and (24,24.55)
m=(24.55-13.00)/(24-13)
m=11.55/11
m=1.05
the equation in point slope form is
m=1.05
(x1,y1)=13,13)
y-13=(1.05)(x-13)
y-13=1.05x-13.65
y=1.05x-0.65
For x=30 donuts
y=1.05(30)-0.65
y=30.85
therefore
Do you save $0.65