Question

A glass of milk is moved from a refrigerator with a temperature of 5∘C to a room with a temperature of 20∘C. One minute later the milk has warmed to a temperature of 7∘ C. After how many minutes does the milk have a temperature that is 90% of the room temperature?

Answer 1

The milk will reach 90% of the room temperature in approximately 4.5 minutes.

Step-by-step explanation:

To find the number of minutes it takes for the milk to reach a temperature that is 90% of the room temperature, we need to first determine the rate at which the milk temperature is increasing.

Let's assume that the rate of change of the milk temperature is constant over time. In the first minute, the milk's temperature increased by 2°C (from 5°C to 7°C). So, we can say that the rate of change of the milk temperature is 2°C per minute.

To find the number of minutes it takes for the milk to reach 90% of the room temperature (20°C), we can set up the following equation:

2*t + 5 = 0.9*20

Where t is the number of minutes.

Solving this equation, we find that t = 4.5 minutes. Therefore, it takes approximately 4.5 minutes for the milk to reach a temperature that is 90% of the room temperature.