Waterway Industries had 470 units of "Dink' in its inventory at a cost of $5 each. It purchased, for $2450.310 more units of Dink: Wathrway then sold 620 units at a selling price of $11 each, resulting in a gross profit of $2820. The cost flow assumption used by Waterway O is weighted average is LIFO. cannot be determined from the information given Is FIFO