Ali sold muffins in boxes of threes and fours. At first he had 5 times as many small boxes as big boxes. After selling 2/5 of the small boxes and some big boxes, he packed another 12 more big boxes. As a result the number of unsold small boxes became twice the number of unsold big boxes. If the total of unsold muffins was 150 how many big boxes did he sell? Asked by wife’s colleague, Lilian Date: 18...