Answer:
If the department store had a 15% off sale on all merchandise, it means that customers paid only 85% of the original price for each item. So, if they took in $8,500 on the first day of the sale, we can set up an equation to solve for the original amount:
Let X be the original amount taken in on the first day of the sale.
Then, we can write:
85% of X = $8,500
0.85X = $8,500
Dividing both sides by 0.85, we get:
X = $10,000
Therefore, if they had sold the same merchandise at the original price, they would have taken in $10,000 on the first day of the sale.