Puzzles - Missing letters puzzles

Exercise : Missing letters puzzles
157.
Answer
:
J
Explanation
:
In each circle, the reverse alphabetical value of the lower letter equals the sum of the alphabetical values of the top 2 letters.

158.
Answer
:
B
Explanation
:
Start at the top left and move down the left hand column, then move one place to the right and up the next column etc. in a snakes and ladders pattern. Letters are written in alternate spaces, in steps of 7 letters at a time.

159.
Answer
:
R
Explanation
:
The sum of the numerical values of letters in opposite segments of the circle is always 22.