Question

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.
Answers
x+y=21,3x+4y=68
x+y=68, 3x+4y=21
x+y=21, 4x+3y=68
x+y=68, 4x+3y=21

Answer 1

Answer: x+y=21, 3x+4y=68

Explanation:

Here x represents the number of small button and y represents the number of large button,

And, According to the question,

Total number of button = 21

Thus,  x + y = 21

Also, She sells the small buttons for $3 and the large buttons for $4, and earns a total of $68

That is,   3x + 4y = 68

Thus, the system of equations that can be used  to calculate the number of large and small buttons sold are,

x + y = 21,  3x + 4y = 68

First Option is correct.

Answer 2

$x+y=21\\3x+4y=68$