the answer is -5x :) I'm pretty sure
Let the number of child tickets sold be x, and number of adult tickets be y, then
5.70x + 9.50y = 543.40 . . . (1)
y = 2x . . . (2)
Putting (2) into (1), gives
5.7x + 9.5(2x) = 543.4
5.7x + 19x = 543.4
24.7x = 543.4
x = 543.4/24.7 = 22
Therefore, 22 child tickets were sold.
<span>2x-7y = 0
2x-7*6=0
2x-42=0
2x=42
x=21
(21,6)</span>
Tim can put 1 music player and 3 pairs of headphones in each of 13 packages.
The greatest number of identical packages Tim can make is 13.