I'm lost...Can someone help. No idea where to start...

For the 18 hour time period beginning at midnight, the temperature F (in degress Fahrenheit) in a particular room is given by the function F(t)=-12sin(t/3)+78, where t is measured in hours

a. To the nearest degree, what is the temperature at 9 AM

b. During which two consecutive hours does the temperature reach a maximum?

c. To the nearest tenth, what is the average temperature for the 18 hour period?

d. If the air conditioning turns on when the temperature is 83 degrees or higher, at what time interval(s) is the air conditioning operating?

Thanks a lot everyone.