A manafature company can sell

Question

A manufacturing company finds that they can sell  items at  per item and  items at  per item. If the relationship between the number of items sold  and the price per item  is a linear one:

Find a formula that gives in terms of :  

Now use the formula to find the number of items they will sell if the price per item is 

Answer 1

(1,3.5), (4,2), (x, 1.5) x>4

slope = -1/2

p= (-1/2)(x-4)+2=-x/2 +6

1.5= -x/2+6

x= 9 hundred sold at $1.50