Question

In which of the following will you be able to buy the lowest cost per pencil?

Store A
$110 for 88 pencils.

Store B
c = 1.10p, where c is the total cost of the pencil and p is number of pencils

Store C
No. of Pencils.
25 = $50.00
32 = $64.00
56 = $112.00

Store D
(Look at the graph)

Answer 1

`\large \boxed{\text{Store B}}`

Explanation:

The formula for the cost per pencil is

`\text{Cost per pencil} = \frac{\text{Total cost}}{\text{Number of pencils}} \text{ or}\\\\C = (c)/(p)`

Store A

`C = \frac{\$110}{\text{88 pencils}} = \text{\$1.25/pencil}`

Store B

`c = 1.10 p\\\\1.10 = (c)/(p)\\\\C = \text{\$1.10/pencil}`

Store C

Pick one of the entries.

`C = \frac{\$112.00}{\text{56 pencils}} = \text{\$2.00/pencil}`

Store D

Pick one of the points on the graph.

`C = \frac{\$6}{\text{4 pencils}} = \text{\$1.50/pencil}\\\\\large \boxed{\textbf{Store B}} \text{ has the lowest cost per pencil}`