It was 15°F at 6 A.M. which means it was morning. Then the time changes to 6 P.M. which means it is now the afternoon. In the time that has passed the temperature increased to 20°F.
(I'm not sure if this was the answer you were looking for but I hope this helped)
not sure if this is correct but 1. A ( reasoning: "Hint: Mitch has to do the opposite of subtract 43 to both sides." which means he had to add. 2. She can get no more than 4
