Here, put the series in increasing order :
20, 20, 21, 25, 30, 30, 33, 45, 54
Now, as the series contains 9 numbers, median would be 5th number which is 30.
Mean = 20 + 20 + 21 + 25 + 30 + 30 + 33 + 45 + 54 / 9 = 30.89
In short, Your Median = 30, Mean = 30.89
Hope this helps!
