Answer:
30 - 3t ≤ 20
Step-by-step explanation:
Given that :
Pool is open when high temperature is higher than 20°C
From 30°C ; temperature decreased at a constant rate in the next three days ; that is the daily fall in temperature for 3 days is the same.
Let the fall or decrease in temperature = t
Constant decrease for 3 days = 3t
Change in temperature over 3 days :
Initial temperature - constant decrease
30°C - 3t
Hence, inequality to determine rate of temperature decrease :
30 - 3t ≤ 20
