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.
6 9 15
8 12 20
4 6 ?

Answer: B. 10

In the first row, 6 x 3/2 = 9,  6 x 5/2 = 15.
In the second row, 8 x 3/2 = 9,  8 x 5/2 = 20.

.'. In the third row, missing number = 4 x 5/2 = 10.