Answer:
1.75 usd.
Step-by-step explanation:
I made the graphic to guide me. Th formula of the function that represents the problem is:
We choose two pairs, for example (2,3.5) and (4,7) and calculate the slope:
m= [tex]\frac{7-3.5}{4-2}=\frac{3.5}{2}= 1.75.[/tex]
And we calculate the equation with the slope and one pair:
(y-7)=1.75(x-4)
y-7=1.75x-7
y=1.75x-7+7
y=1.75x.
Then, for x=1, this is one pen the price (the y value) is
y=1.75(1)=1.75, yu can see also the aproximation of the result with the graphic.
