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.
13
12
5
17
15
8
25
24
?
29
21
20
Answer: A. 7
Clearly, (3rd column)2 + (2nd column)2 = (1st column)2 In the first row, 52 + 122 = 132. In the second row, 82 + 152 = 172. Let the missing number in the third row be y. Then y2 + 242 = 252 or y2 + 576 = 625 or y2 = 49 or y = 7.