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.
3 15 4
7 38 5
3 ? 5

Answer: B. 18

In the first row, 3 x 4 + 3 = 15.
In the second row, 7 x 5 + 3 = 38.
.'. In the third row, missing number = 3 x 5 + 3 = 18.