Answer: Option A. -> 34
Logic:
Column-Wise
(First Column Element × 4th Column element) - (2nd column element + 3rd Column element) = Last Column Element
(4×2)-(5+3) = 0
(7×4)-(3+4) = 21
(6×5)-(4+4) = 22
(9×5)-(6+5) = 34.

Answer: Option B. -> 4
In the first column,
27- 7*2 = 13
In the second column,
144 - 45*2 = 54
So,
in the third column,
68 -32*2 = 4

Answer: Option B. -> 10
First Method
Row-wise Logic:
First element + second element = Third Element.
6 + 9 = 15
8 + 12 = 20
4 + 6 = 10
So, required number is 10.
Second Method
Logic:
Second Row element - first row element = Result * 2 = Third Row Element.
Column 1:
8 - 6 = 2
2 *2 = 4
Column 2:
12 - 9 = 3
3 *2 = 6
Column 3:
20 - 15 = 5
5 * 2 = 10.
Required Number is 10.
Third Method:
In the First row,
6*(3/2)= 9.
6*(5/2) = 15.
In the second row,
8*(3/2) = 12.
8*(5/2) = 20.
hence,
In the third row,
missing number,
= 4*(5/2) = 10.

Answer: Option D. -> 51
Logic:
First Row Element - Third Row Element = Second Row Element.
56 - 44 = 12
65 - 14 = 51
78 - 48 = 30.
Hence, in the missing number should be 51.

Answer: Option B. -> 18
20 = 8 x 2 + 4
15 = 3 x 2 + 9
Hence,
The number on the blank space,
6 x 2 + 6 = 18.

Answer: Option B. -> 4
Logic (Moving-Down):
7122 = 7 + 1 + 2 + 2 = 12.
6521 = 6 + 5 + 2 + 1 = 14.
8332 = 8 + 3 + 3 + 2 = 16.
4743 = 4 + 7 + 4 + 3 = 18.
9911 = 9 + 9 + 1 + 1 = 20.
So, sum of the last oval box = 22.
387x = 3 + 8 + 7 + x = 22.
x = 22 - 18 = 4.
Missing Element = 4.

Answer: Option B. -> 6
The number in the centre of each star equals the average of the surrounding 5 numbers. So,
Central number of last figure = ( 7 + 7 + 2 + 2 + 12)/5.
X * 5 = 30
X = 6.

Answer: Option A. -> 2
Working in rows, the sum of numbers in each row follows the sequence 5, 10, 15, 20, 15, 10, 5. So,
Sum of the middle = 20
1 + 3 + 7 + x + 1 + 4 + 2 = 20
x = 20 - 18 = 2.
Missing element = 2.

Answer: Option C. -> 9
Working from left to right, the sum of the two smaller numbers on each triangle equals the third number. And the bigger number is rotating clockwise. So, in third triangle,
Missing Element,
x + 6 = 15.
x = 15 - 6 = 9.

Answer: Option D. -> 1
Logic:
Element in Lower left segment = Sum of the upper segment element
Element in Lower right Segment = Difference of the Upper segment element
Missing Number = 5 - 4 = 1.