Answer
Both discovered expressions are the same: $\left[\frac{n+1}{2}\right]$. This means that it can
be used to calculate the average number of comparisons.
Work Step by Step
The expressions that we discovered in parts (a) and (b) are one and the
same. Since we have analyzed both possibilities for $n,$ even and odd, we
can say that our expression is the one we can use to calculate the average
number of comparisons using sequential search in an n-element list.
$\frac{n+1}{2}$