Temperature fell 25° [tex]\\[/tex]
5 PM => 20
10 PM => -5
Find the difference between both temperatures at 5 PM and 10 PM
T = 20 - ( -5) = 20 + 5 = 25
The reason we subtracted 10 PM from 5 PM (20 - ( -5)) and not the other way around is because 5 PM obviously comes before 10 PM.