Question

The teachers’ edition of a statistics textbook sells for $150, and students’ edition of the book sell for $50 each. Which function can be used to find the average cost per book if two teachers’ editions and x students’ editions are purchased?
a) f(x)= 150+50x over 1+x
b) f(x)= 150+50x over 2+x
c) f(x)= 300+50x over 1+x
d) f(x)= 300+50x over 2+x

Answer 1

Average =
Sum of all / total number of things

The sum of that would be 300 + 50x
The total number of things would be 2+x

Therefore it is 
(300+50x) /2+x

Answer 2

Answer: d) f(x)= 300+50x over 2+x

Step-by-step explanation:

Since, the money earned by a teacher in selling a book = $ 150

⇒ The money earned by 2 teacher = $ 300

Now, the money earned  by a student in selling the book = $ 50

⇒ The money earned by x students = 50x

Thus, the total collection by 2 teacher and x students = 300 + 50x

And, the total persons = 2 teachers + x students = 2 + x

$\text{ The average collection}=\frac{\text{ Total collection}}{\text{Total persons}}$

$=\frac{300+50x}{2+x}$

⇒ Option d) is correct.