Which one will replace the question mark?

(10 + 9 + 14 + 7)/2 = 20

and (11 + 16 + 10 + 13)/2 = 25

Therefore, (15 + ? + 12 + 10)/2 = 22

Hence 37 + ? = 44

? = 44 - 37

? = 7.

(5 + 4 + 7)/2 = 8

(6 + 9 + 5)/2 = 10

(3 + 7 + 2)/2 = 6.

13 + 15 = 28

36 + 54 = 90

Therefore, 45 + 63 = 108.

(2 x 2 - 1) = 3

and (5 x 4 - 5) = 15

(5 x 5 - 3) = 22.

(4)² + (2)² + (1)² = 21

and (5)² + (3)² + (8)² = 98

Therefore (6)² + (7)² + (3)² = 94.

(4 x 8) + 1 = 33

(5 x 9) + 1 = 46

Similarly, (7 x 11) + 1 = 78.

(15 x 2 - 3) = 27,

(31 x 2 - 6) = 56

and (45 x 2 - 9) = 81

3 x 5 x 4 = 60

and 5 x 7 x 4 = 140

Therefore, 4 x 4 x ? = 96

? = (96/16) = 6.

Sum of numbers in lower half of the circle = 11 + 9 + 3 + 7 = 30

Sum of numbers in upper half of the circle = ? + 4 + 5 + 6 = ? + 15

Upper half = Lower half

30 = ? + 15

? = 30 - 15

? = 15.

Threfore, 15 is the answer.

How the number is obtained?

2 + 4 = 6

5 + 9 = 14

Similarly,

3 + 5 = 8

Therefore, the answer is K₈.