In this 4x4 grid, each of the capital letters in bold represents a different base ten digit from 0 to 9, such that the sum of each of the four columns as well as the sum of each of the four rows is ET.

E   L   M   S
R   E   I   N
A   N  T   I
S   T   E   P

Determine the respective minimum value and the maximum value of ET.

Note: ET is equal to 10*E+ T.