The median of the date 21,22,23,24,25,26,27,28, is

21,22,23,24,25,26,27,28

Number  of terms “8” even

Median $=$ Average of  $\frac{n^{th}}{2}$ term , ${\left(\frac{n}{2}+1\right)}^{th}$ term

$\frac{8}{2}=$ 4^th , $\frac{8}{2}+1=4+1=5^{th}$

4^th term $=24$

5^th term $=25$

Median $=\frac{24+25}{2}=24.5$