Question

Recycled​ CDs, Incorporated, offers a choice of 5 used CDs for ​$28​, with each additional CD costing ​$5. Write a cost function for purchasing 5 or more CDs. What will the cost of buying 9 CDs​ be? Let x represent the number of CDs over 5.

Answer 1

$28 + 5x$
In terms of x

Answer 2

Answer:

$28+5\text{x}$ and $\ 48$

Step-by-step explanation:

Given: Recycled​ CDs, Incorporated, offers a choice of 5 used CDs for ​$28​, with each additional CD costing ​$5

To Find: cost function for purchasing 5 or more CDs, the cost of buying 9 CDs, Let x represent the number of CDs over 5.

Solution:

Cost of buying 5 used CDs $=\ 28$

Cost of additional CD $=\ 5$ $\text{per CD}$

now,

number of CDs over $5$$=\text{x}$

cost function for purchasing $5$ or more CDs =$\text{fixed cost of 5 CD}+ 5\times\text{no. of additional CD}$

                $=28+5\text{x}$

Now,

Cost of buying $9$ CDs

one will buy $4$ additional CDs

                                       $=28+5\times4$

                                       $=28+20$

                                       $=\ 48$

Hence, cost function for purchasing 5 or more CD is  $28+5\text{x}$, and cost of buying $9$ CD is  $\ 48$