The swimming pool is open when the high temperature is higher than 20^\circ\text{C}20 ∘ C20, degrees, start text, C, end text. Lainey tried to swim on Monday and Thursday (which was 333 days later). The pool was open on Monday, but it was closed on Thursday. The high temperature was 30^\circ\text{C}30 ∘ C30, degrees, start text, C, end text on Monday, but decreased at a constant rate in the next 333 days.