Using elimination, we add the equations, but this time from left to right. This process wants to elimination a variable. So 2x plus -2x equals 0. Moving on the next variable, 6y plus -y is 5y. On to the last variable, 18 plus 12 is 30. So we have this equation, 5y=30. 30/5 is 6, so y=6. We plug 6 into y in one of the equations you choose. In this case, I'm going to use the first equation. Plugging 6, we have this equation, 2x plus 36 is 18. 18-36 is -18. We then have this equation, 2x=-18. We know -9 times 2 is -18, so our x value is -9, So, our y=6, and our x=-9.
We know that Sally picked 6 2/3 pounds of apples, which can be converted into an improper fraction: 20/3. Multiply 20/3 and 1/2. You will get 20/6, which is 3 1/3. Hope this helped :D