LOGICAL REASONING

1) What is the missing letter in this series:

a a b b ? c

2) What is the missing letter in this series:

c c d ? e f g g h

3) What is the missing letter in this series:

a z b ? c x

4) What is the missing letter in this series:

f g e h d i c ?

5) What is the missing letter in this series:

r q p r q p ?

6) What is the missing letter in this series:

b e h k n ? t

7) What is the missing letter in this series:

y e w g u i ?

8) What is the missing letter in this series:

x ? p l h

9) What is the missing letter in this series:

c c d f i ?

10) What is the missing letter in this series:

j g d k ? e l

11) What is the missing letter in this series:

a b d h ?

12) What is the missing letter in this series:

b g d i ? k h

13) What is the missing letter in this series:

a d i ?

14) What is the missing letter in this series:

g ? d i j d k l d

15) What is the missing letter in this series:

p q q ? s s t u

16) What is the missing letter in this series:

g g k k o o ?

17) What is the missing letter in this series:

y e u i q m ?

18) What is the missing letter in this series:

v s p w t q ?

19) What is the missing letter in this series:

a b k c d k e ?

20) What is the missing letter in this series:

q r k s t i u v ?

21) What is the missing letter in this series:

c j q x e ? s

22) What is the missing letter in this series:

y d j w f l u h ?

23) What is the missing letter in this series:

m o n n o m p ?

24) What is the missing letter in this series:

c d c d d d e d e ?

25) What is the missing letter in this series:

a b b d c f d ?

26) What is the missing letter in this series:

b c e g k ? q s

27) What is the missing letter in this series:

m n n o o ? p p p

ANSWER KEY

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

j kl mnopqrst uvwxyz

Question Answer How to work out the answer

1 3 c Letters increment by one every second letter.

2 4 e ccd ... Eef ... ggh!

3 5 y Ist letter of alphabet, then last, 2nd, 2nd last, 3rd, 3rd last

4 3 j 2 interspersed sequences. First decreasing by one: fedc and second increasing by one: ghi J

5 4 r Letters are in triplets decreasing by one. rqp ... rqp .... Rqp

6 3 q Letters go up by three each time. 2nd letter of alphabet, 5th 8th etc.

7 1 s 2 interspersed sequences again. First one decrementing by 2, second incrementing by 2

8 5 t Letters decrement by 4 each time

9 4 m The gap between letters increases by one each time 0, 1, 2, 3, 4

10 1 h Letters are in triplets which decrement by 3, but starting letter of each triplet increments

by one: 10,7,4 ... 11,8,5

11 5 p Letters double each time 1, 2, 4, 8, 16 - n

12 4 f 2 seqences interspersed, both incrementing by 2 each time

13 1 p Sequence of squares according to place in alphabet: 1, 4, 9, 16 - p

14 4 h Take out the d's and you get a simple alphabetical sequence!

15 1 r Letter are in triplets: letter, letter+1, letter+1, then triplet repeats but incremented by 2.

16 2 s Letters are in pairs which increment by 4 places in the alphabet each time.

17 1 m The odd letters decrement by 4 each time.

18 3 x Each whole triplet increments by one, whilst the letters in the triplet decrease by 3.

19 1 f Take out the k's and you have a simple alphabetical sequence.

20 5 g Each third letter descends by 1

21 2 l Each letter increments by 7, the alphabet wraps round.

22 3 n Each third letter increments by 2

23 1 l The even letters decement by one each time.

24 3 f These are triplets, the first and the last letter of the triplet increments by 1 each triplet.

25 4 h Every second letter increments by 2

26 2 m Getting hard now! Prime numbers.

27 5 o 1 m, 2 n's, 3 o's, 4 p's.