Kareem has 216 role-playing game cards. his goal is to collect all 15 sets of cards. there are 72 cards in a set. how many more cards does kareem need to reach his goal?

C= cards and S = sets and G = goal and X = the amount needed to reach the goal

72 C = 1 S

G = 15S 

and 15 S is equal to 15 multiplied by 72C

15(72C) =G 

1080C = G 

if he already has 216 cards then 

216C + X = 1080C

you should be able to figure out the rest :) Good luck and PM for additional questions