Final answer:
The price of the product yesterday was $15.84, which is calculated by adding the decline of $0.38 to today's price of $15.46.
Step-by-step explanation:
To find the price of the product yesterday, we need to add the decline in price back to today's price. Since the product declined by $0.38 to reach today's price of $15.46, we can calculate yesterday's price as follows:
Yesterday's Price = Today's Price + Decline
Yesterday's Price = $15.46 + $0.38
Yesterday's Price = $15.84