Explanation:
light blue.
our function needs to calculate r out of h.
P does not recognize h (hours after midnight) as parameter. P needs c as input.
T needs h as input and delivers c as output.
therefore (P ○ T)(h) = r is correct.
first the "inner" T function is calculated with h as parameter and then P is calculated using the result from T (c) as input and delivers r.