Question

The table below shows the total cost of buying printer ink cartridges for both members and nonmembers of a shopping club.

Price of Ink at Shopping Club
Number of ink cartridges purchased
Total cost for
members
(with membership fee)
Total cost for nonmembers
0
$30
0
1
$40
$25
2
$50
$50
3
$60
$75

Which statement is supported by the table?
The relationship between the number of cartridges purchased and the total cost is proportional for nonmembers but not for members.
The relationship between the number of cartridges purchased and the total cost is proportional for members but not for nonmembers.
The relationship between the number of cartridges purchased and the total cost is proportional for neither members nor nonmembers.
The relationship between the number of cartridges purchased and the total cost is proportional for both members and nonmembers.

Answer 1

The relationship is proportional for nonmembers but not for members.

Reason: Nonmember cost = $25 per cartridge (0→$0, 1→$25, 2→$50, 3→$75), so cost is 25×number of cartridges. Member cost includes a $30 membership fee (0→$30), so it does not pass through the origin and is not proportional.