#### 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.
$\frac{n+1}{2}$