T = 18 + 12h
Student can not get outside if T <= 32f
to find when will T = 32
32 = 18 +12 h
h = 7/6 ~ 1.2 hour
mid night = 12 am
at 11:30 am , -> temprature < 32 no one can get out
at 11:00 am, -> no one can get out
12:00 pm:
h = 12
T(h) = 18 + 12 x 12 = 162 f
students can get out
for h > 12