Answer:
5c + 15 ≥ 85; 14 packs of cards
Explanation:
Joel already has 15 and each pack has 5 cards in it.
We will use a variable, c, to represent the amount of packs Joel needs to purchase in order to have at least 85 cards.
Since Joel wants at least 85 cards, that means he wants 85 or more.
5c + 15 ≥ 85
Subtract 15 from 85 since Joel already has that amount of cards.
5c ≥ 70
Then isolate the variable and divide 5 on both sides.
c ≥ 14
Joel needs at least 14 more packs of cards.