Sam shade purchased 260 lampshades at $10 each with terms of 3/15, n/30 from Lois lamps on November 1. These lampshades had a cost of $5 each to Lois lamps. On November 5, Sam shade returned 20 lampshades and received credit of $10 each from Lois lamps. Lois lamps will return these shades into their inventory at their original cost of $5 each. On November 15, same shade paid the balance owed less the return and discount.