9. At midnight, the temperature in a city was 5 degrees Celsius. The temperature was dropping at a steady rate of 2 degrees Celsius per hour. Which inequality represents t, the number of hours past midnight, when the temperature was colder than -4 degrees Celsius. *
1 point
A 5t - 2 > -4
B 5 - 2t > -4
C 5 - 2t < -4
D 5t - 2 < -4
b c a
To solve this problem, we need to determine the number of hours past midnight when the temperature was colder than -4 degrees Celsius.
Let's analyze the given information:
- The initial temperature at midnight is 5 degrees Celsius.
- The temperature is dropping at a steady rate of 2 degrees Celsius per hour.
- We want to find the number of hours past midnight when the temperature is colder than -4 degrees Celsius.
To represent the temperature at a given time, we can use the equation:
Temperature = Initial temperature - Rate of change * Number of hours
Using this equation and the given information, we can represent the temperature as follows:
Temperature = 5 - 2t, where t is the number of hours past midnight.
Now, we need to find the inequality that represents the condition when the temperature is colder than -4 degrees Celsius.
The inequality "Temperature < -4" can be written as:
5 - 2t < -4
Simplifying this inequality, we get the final answer:
5 - 2t < -4
Therefore, the correct inequality that represents the number of hours past midnight when the temperature was colder than -4 degrees Celsius is option C: 5 - 2t < -4.