In the following question, a matrix of certain characters is given. These characters follow a certain trend, row-wise or column-wise. Find out this trend and choose the missing character accordingly.
2 4 0
1 2 4
3 1 3
36 ? 91

Answer: D. 73

Clearly, (1st row)2 + (2nd row)2 + (3rd row)2 = 4th row.
So, in the first column, 22 + 13 + 33 = 8 + 1 + 27 = 36.
In the third column, 03 + 43 + 33 = 0 + 64 + 27 = 91.
.'. In the second column, missing number = 43 + 23 + 13 = 64 + 8 + 1 = 73.