Final answer:
The exact cooling time cannot be determined without additional data on the rate of cooling and surrounding conditions. Rapid cooling is recommended for food safety.
Step-by-step explanation:
To answer the student's question, we cannot determine the exact time left to cool the soup down to 41°F (5°C) without more information. Cooling does not occur at a constant rate as it is influenced by the difference in temperature between the object cooling and its surroundings, as well as the specific heat capacity of the substance and the surface area that is exposed to the cooler environment.
However, using Problem-Solving Strategies for the Effects of Heat Transfer, you can calculate the time if the rate of cooling and other relevant data are provided. It's also important to note that perishable foods, such as soup, should be cooled rapidly to prevent bacterial growth and should never be left at a temperature between 40 and 140 degrees Fahrenheit for more than two hours without being refrigerated.