Answer:
d
Explanation:
Lets have a look at what is given:
Teachers edition of statistics textbook sells for $150
Students edition of statistics textbook sells for $50.
Two teachers and x student books are purchased.
Let f(x) = the average cost per book
Therefore the amount of the teachers textbook cost 2*$150 = $300
and the students texbook costs x*$50= $50x
The average cost per book is:
f(x) = (300+50x)/(x+2)