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.
51 11 61
64 30 32
35 ? 43

Answer: B. 27

In the first row, 5 x 1 = 5, 6 x 1 = 6,  5 + 6 = 11.
In the second row, 6 x 4 = 24,  3 x 2 = 6,  24 + 6 = 30.
In the third row, 3 x 5 = 15,  4 x 3 = 12.
.'. Missing number = 15 + 12 = 27