you can simplify the expression in b (iii) by letting
to resemble f(x)
so
a (iii)
therefore
so
when
, or in other words, its still above ground.
disregarding the first T seconds, this means the time it took to reach max height (T seconds), is not long enough for the object to reach the ground. so that means it takes longer to fall to the ground than rise.
theres probably a better explanation