What is the correct answer for Landon's problem? Explain where he went wrong.

Graph red beads cost $1 an ounce and gold beads cost $3 an ounce. juanita wants to purchase a 12-ounce mixture of red and gold beads that she can sell for $2 an ounce. the solution of the system shows the number of beads needed for juanita to break even. x + y = 12, x + 3y = 24 how many ounces of red beads will juanita buy to break even? how many ounces of gold beads will she buy?

Complete the solution of the equation. find the value of y when x equals to 28 x+3y=28

Iknow the answer but the calculator doesn't seem to give the right one