Answer:
Your answer would be x+y=531 and y=2x
Explanation:
We know that Nancy bought 531 shirts and that some are long sleeved and some are short sleeved. Since x represents the long sleeved shirts and y represents the short sleeved shirts, x+y=531. We also know that there are twice as many short sleeved shirts as long sleeved shirts. So, y=2x.