A snack bar sells two sizes of snack packs. A large snack pack costs 5 dollars. A small snack pack costs 3 dollars. In one day the snack bar sells 60 snack packs for a total of 220 dollars how many small snacks packs did they sell.

X=cost of large snack Y=cost of small snack X+Y=60 5X+3Y=220 To solve for y, solve x+y=60 for x. Subtract y from both sides so you're left with x=-y+60. You now plug in - y+60 for x in the second equation. 5 (-y+60) + 3y=220 - 5y+300+3y=220 - 2y+300=220 - 2y=-80 Y=40 40 small snack packs is the final answer