The hourly temperature recorded by an automatic weather station forms an arithmetic progression. The temperature at the 2nd hour is 28∘C and at the 12th hour it is 8∘C.
a. (i) Determine the temperature at the 1st hour and the common difference.
b. (ii) Obtain a formula for the temperature Tn at the nth hour.
c. (iii) Find the earliest hour when the temperature will drop below 0∘C.