Answer:
Inequality: 30 - 3d ≤ 20
Rate of decrease from Monday to Thursday: greater than or equal to 10/3 degrees Celsius per day
Step-by-step explanation:
Translate theconditions into mathematical terms:
HIgh temperature on Monday = T₀ = 30°C.
The temperature decrease at a constant rate in the next 3 days. Call d such rate, so T₃ = T₀ - 3d = 30 - 3d
That the pool is open when the high temperature is higher than 20°C means that, if the pool is closed, then the temperature is less than or equal to (≤) 20°C:
30 - 3d ≤ 20
And that is the requested inequality.
From that, you can solve for the rate of temperature decrease, d:
Add 3d to both sides: 30 ≤ 20 + 3d
Subtract 20 from both sides: 10 ≤ 3d
Divide both sides by 3: 10/3 ≤ d
Apply symmetry property: d ≥ 10/3
Hence, the rate of temperature decrease is greater than or equal to 10/3 degrees Celsius per day, from Monday to Thursday.
