
11. 

Answer: B
Explanation:
Add together the numerical values of the letters in corresponding positions on the left and right hand triangles, and put the letter with this value in corresponding segments of the centre triangle.

12. 

Answer: A
Explanation:
Start on the centre left of the diagram, and move in a clockwise spiral towards the centre. Letters advance through the alphabet in steps of 2,3, 4, etc.

13. 

Answer: T
Explanation:
Working through the diagram in columns, left to right, The sum of the numerical values of the letters in each column follows the sequence 17,18, 19 and 20.

14. 

Answer: Z
Explanation:
Read the diagram as a whole grid of 4x4 squares. Starting on the bottom left square, move clockwise around the outside of the whole square,with letters written in sequence, skipping 4 letters at a time. Repeat this instruction for the small inner square.

15. 

Answer: X
Explanation:
Start at the top left and move in alternate boxes from left to right,then down one row and to the left, in a snakes and ladders pattern. Letters advance through the alphabet in steps of 2, 3, 4...8, before repeating this pattern.


