Question 719060
Solution:

Let the sum of 5 numbers be 'X'.
Let the excluded number  be 'y'

Average of 5 numbers = X/5 = 27 or X = 135
Average of 4 numbers = (X-y)/4 = 25 or X-y = 100
OR y = X-100 = 135-100 = 35

Excluded number is 35