Puzzles - Logical puzzles

10.
Answer
:
B
Explanation
:
In each row of the diagram, the reverse alphabetical value of the central letter equals the sum of the left and right hand digits.

11.
Answer
:
G
Explanation
:
Convert each letter to its numerical value, and read each pair of values as 2 digit numbers. In each row, the number in the centre equals the difference between the 2 digit values on the left and right.

12.
Answer
:
Y
Explanation
:
Start in the top left hand corner and move anti clockwise around the perimeter of the square. Letters are written in alphabetical order, skipping 1 letter, then 2 letters, then 3 etc.