The marketing department for a large sporting equipment store determined that 82% of the customers who purchase an item on sale also purchase at least one item not on sale. Based on this information, if 2,500 customers purchase an item on sale the day after Thanksgiving, how many of these customers will also purchase at least one item not on sale?

Out of the 2,500 customers who purchase an item on sale, 82% also purchase at least one item not on sale.

Therefore, 82% of 2,500 is:
0.82 x 2,500 = 2,050 customers

So, 2,050 customers will also purchase at least one item not on sale.