The swimming pool is open when the high temperature is higher than 20°c. lainey tried to swim on monday
and thursday (which was 3 days later). the pool was open on monday, but it was closed on thursday. the high
temperature was 30°c on monday, but decreased at a constant rate in the next 3 days.
write an inequality to determine the rate of temperature decrease in degrees celsius per day, d, from monday
to thursday.