Answer:
Step-by-step explanation:
Let d represent the rate of temperature decrease in degrees Celsius per day from Monday to Thursday.
As temperature decreased at a constant rate in the next 3 days, so the rate of temperature will decrease 3d degree Celsius in 3 days.
We are told that the pool was open on Monday. The high temperature was on Monday. So the decrease in temperature from Monday to Thursday will be
.
We have been given that the swimming pool is open when the high temperature is higher than .
As the pool was closed on Thursday. This means that temperature on Thursday was less than or equal to 20 degree Celsius. We can represent this information in an inequality as:
Therefore, the inequality can be used to determine the rate of temperature decrease in degrees Celsius per day, d, from Monday to Thursday.