Kara has 21 collectible buttons to sell. She sells the small buttons for $3 and the large buttons for $4, and earns a total of $
68. If the small buttons are represented by x and the large buttons are represented by y, which of the following systems of equations can be used to calculate the number of large and small buttons sold? (5 points)
System of equations that can be used to solve for both x and y are: x + y = 21 (since she sold 21 all together) 3x + 4y = 68 (cost of each and total earned)
