Question

Mrs tan baked some muffins and packed them i big and small boxes for sale.Each big bbox contained 4 muffins and each small box contained 2 muffins.At first,there were 4 times as many small boxes as big boxes.After she had sold half of the small boxes and some big boxes,she baked some more muffins and packed them into 5 big boxes.How many big boxes of muffins did she sell if she had 360 muffins left?