Answer
(a) 12 noon to 8 P.M.
(b) from midnight to 6 a.m., and after 10 p.m.
(c) 10a.m and 8:30p.m.
(d) See explanations.
Work Step by Step
(a) Locate $T=55^\circ $ vertically, go horizontally to meet the curve, read its hour as $12, 20\ hr$ thus from 12 noon to 8 P.M. above $55^\circ $.
(b) The temperature was at $40^\circ $ from midnight to 6 a.m., below $40^\circ $ after 10 p.m.
(c) The temperature at noon in Bratenahl was $55^\circ $, $55-7=48$ corresponds to 10 and 20.5 hr in Bratenahl, and at those times the temperature in Greenville was 7 degree higher, thus at 10a.m and 8:30p.m. the temperature in Greenville the same as the temperature at noon in Bratenahl.
(d) Answer may vary. An example is: during a 24-hr period in Bratenahl, the temperature was steady at about $40^\circ $ from midnight to 6 a.m., then increasing from 6 a.m. to 4 p.m. to a maximum of about $65^\circ $, decreasing from 4 p.m. to midnight to just below $40^\circ $.