Looking at the table, the temperature in Boston at 6 AM is -8°F.
(a)
If the temperature had risen by 17°F at noon, then the new temperature is:
[tex]-8\degree F+17\degree F=9\degree F[/tex]
(b)
The 6 AM temperature in Toronto was -16°F, and -25°F in Fairbanks. The difference is:
[tex]-16\degree F-(-25\degree F)=-16\degree F+25\degree F=9\degree F[/tex]
