Barbara buys a box of pens for $4. For every additional box she buys, she gets a $1 discount. Which expression represents the total cost of the pens, c, as a function of the number of boxes, b?

A. c=f(b)=4b-1
B. c=f(b)=4b+1
C. c=f(b)=3b+4
D. c=f(b)=4b+3
E. c=f(b)=4+3(b-1)

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ApusApus ApusApus · Answer 1 · 2019-04-06T13:05:47+02:00

Answer:

E. [tex]c(b)=4+3(b-1)[/tex]

Step-by-step explanation:

Let b represent the number of boxes.

We have been given that Barbara buys a box of pens for $4, so the cost of 1st box will be $4.

Now the number of boxes without 1st box will be [tex]b-1[/tex].

We are also told that for every additional box she buys, she gets a $1 discount, so the cost of b boxes without 1st box will be [tex]3(b-1)[/tex].

The total cost of all the boxes will be cost of 1st box plus cost of b boxes.

[tex]\text{Total cost of boxes}=4+3(b-1)[/tex]

Since we need to represent the total cost of the pens, c, as a function of the number of boxes (b), so our function will be:

[tex]c(b)=4+3(b-1)[/tex]

Therefore, our required function is [tex]c(b)=4+3(b-1)[/tex] and option E is the correct choice.