Final answer:
Walmart sold 94 hot-water bottles and 376 thermometers in December.
Step-by-step explanation:
Let's assign variables to the number of thermometers and hot-water bottles sold. Let x represent the number of hot-water bottles and 4x represent the number of thermometers sold.
Since the price of each thermometer is $2 and each hot-water bottle is $8, we can create the equation 2(4x) + 8x = 1504 to represent the total sales.
Simplifying the equation, we have 8x + 8x = 1504, which further simplifies to 16x = 1504.
Dividing both sides by 16, we find that x = 94. Therefore, Walmart sold 94 hot-water bottles and 4 times that amount, or 376, thermometers.